diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Api/AsyncSearch/SubmitAsyncSearchRequest.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Api/AsyncSearch/SubmitAsyncSearchRequest.g.cs
index b520e8e6934..b6402bbc452 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Api/AsyncSearch/SubmitAsyncSearchRequest.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Api/AsyncSearch/SubmitAsyncSearchRequest.g.cs
@@ -911,6 +911,7 @@ public SubmitAsyncSearchRequest(Elastic.Clients.Elasticsearch.Serverless.Indices
 	/// <para>List of stored fields to return as part of a hit. If no fields are specified,<br/>no stored fields are included in the response. If this field is specified, the _source<br/>parameter defaults to false. You can pass _source: true to return both source fields<br/>and stored fields in the search response.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("stored_fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? StoredFields { get; set; }
 	[JsonInclude, JsonPropertyName("suggest")]
 	public Elastic.Clients.Elasticsearch.Serverless.Core.Search.Suggester? Suggest { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Api/FieldCapsRequest.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Api/FieldCapsRequest.g.cs
index 50da60c7d13..3e095a8a945 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Api/FieldCapsRequest.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Api/FieldCapsRequest.g.cs
@@ -134,6 +134,7 @@ public FieldCapsRequest(Elastic.Clients.Elasticsearch.Serverless.Indices? indice
 	/// <para>List of fields to retrieve capabilities for. Wildcard (`*`) expressions are supported.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? Fields { get; set; }
 
 	/// <summary>
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Api/SearchMvtRequest.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Api/SearchMvtRequest.g.cs
index 723b8947184..a99f2f68fa6 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Api/SearchMvtRequest.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Api/SearchMvtRequest.g.cs
@@ -79,6 +79,7 @@ public SearchMvtRequest(Elastic.Clients.Elasticsearch.Serverless.Indices indices
 	/// <para>Fields to return in the `hits` layer. Supports wildcards (`*`).<br/>This parameter does not support fields with array values. Fields with array<br/>values may return inconsistent results.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? Fields { get; set; }
 
 	/// <summary>
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Api/SearchRequest.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Api/SearchRequest.g.cs
index 00964457f2f..8596c68bef3 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Api/SearchRequest.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Api/SearchRequest.g.cs
@@ -956,6 +956,7 @@ public SearchRequest(Elastic.Clients.Elasticsearch.Serverless.Indices? indices)
 	/// <para>List of stored fields to return as part of a hit.<br/>If no fields are specified, no stored fields are included in the response.<br/>If this field is specified, the `_source` parameter defaults to `false`.<br/>You can pass `_source: true` to return both source fields and stored fields in the search response.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("stored_fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? StoredFields { get; set; }
 
 	/// <summary>
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Aggregations/MatrixStatsAggregation.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Aggregations/MatrixStatsAggregation.g.cs
index 0b62e92f7da..fc13e84baf2 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Aggregations/MatrixStatsAggregation.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Aggregations/MatrixStatsAggregation.g.cs
@@ -33,6 +33,7 @@ public sealed partial class MatrixStatsAggregation
 	/// <para>An array of fields for computing the statistics.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? Fields { get; set; }
 	[JsonInclude, JsonPropertyName("meta")]
 	public IDictionary<string, object>? Meta { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Aggregations/SignificantTextAggregation.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Aggregations/SignificantTextAggregation.g.cs
index 01662e97bf2..a8653ec6ba8 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Aggregations/SignificantTextAggregation.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Aggregations/SignificantTextAggregation.g.cs
@@ -133,6 +133,7 @@ public sealed partial class SignificantTextAggregation
 	/// <para>Overrides the JSON `_source` fields from which text will be analyzed.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("source_fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? SourceFields { get; set; }
 
 	public static implicit operator Elastic.Clients.Elasticsearch.Serverless.Aggregations.Aggregation(SignificantTextAggregation significantTextAggregation) => Elastic.Clients.Elasticsearch.Serverless.Aggregations.Aggregation.SignificantText(significantTextAggregation);
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Aggregations/TopHitsAggregation.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Aggregations/TopHitsAggregation.g.cs
index 37e0bdd076f..e423e5a1dd3 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Aggregations/TopHitsAggregation.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Aggregations/TopHitsAggregation.g.cs
@@ -33,6 +33,7 @@ public sealed partial class TopHitsAggregation
 	/// <para>Fields for which to return doc values.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("docvalue_fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? DocvalueFields { get; set; }
 
 	/// <summary>
@@ -102,6 +103,7 @@ public sealed partial class TopHitsAggregation
 	/// <para>Returns values for the specified stored fields (fields that use the `store` mapping option).</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("stored_fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? StoredFields { get; set; }
 
 	/// <summary>
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Core/MGet/MultiGetOperation.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Core/MGet/MultiGetOperation.g.cs
index 5984b34f90f..4ce180b8146 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Core/MGet/MultiGetOperation.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Core/MGet/MultiGetOperation.g.cs
@@ -57,6 +57,7 @@ public sealed partial class MultiGetOperation
 	/// <para>The stored fields you want to retrieve.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("stored_fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? StoredFields { get; set; }
 	[JsonInclude, JsonPropertyName("version")]
 	public long? Version { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Core/Mtermvectors/MultiTermVectorsOperation.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Core/Mtermvectors/MultiTermVectorsOperation.g.cs
index f10a8526f9d..d59f293fd89 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Core/Mtermvectors/MultiTermVectorsOperation.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Core/Mtermvectors/MultiTermVectorsOperation.g.cs
@@ -39,6 +39,7 @@ public sealed partial class MultiTermVectorsOperation
 	/// <para>Comma-separated list or wildcard expressions of fields to include in the statistics.<br/>Used as the default list unless a specific field list is provided in the `completion_fields` or `fielddata_fields` parameters.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? Fields { get; set; }
 
 	/// <summary>
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Core/Reindex/Source.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Core/Reindex/Source.g.cs
index d54256f2444..041d861ac77 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Core/Reindex/Source.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Core/Reindex/Source.g.cs
@@ -68,6 +68,7 @@ public sealed partial class Source
 	/// <para>If `true` reindexes all source fields.<br/>Set to a list to reindex select fields.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("_source")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? SourceFields { get; set; }
 }
 
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Core/Search/HighlightField.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Core/Search/HighlightField.g.cs
index d8bd57e35cb..e66e9ec3777 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Core/Search/HighlightField.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Core/Search/HighlightField.g.cs
@@ -78,6 +78,7 @@ public sealed partial class HighlightField
 	[JsonInclude, JsonPropertyName("highlight_query")]
 	public Elastic.Clients.Elasticsearch.Serverless.QueryDsl.Query? HighlightQuery { get; set; }
 	[JsonInclude, JsonPropertyName("matched_fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? MatchedFields { get; set; }
 
 	/// <summary>
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Core/Search/InnerHits.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Core/Search/InnerHits.g.cs
index 6a4340d078a..4524227c6a4 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Core/Search/InnerHits.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Core/Search/InnerHits.g.cs
@@ -36,6 +36,7 @@ public sealed partial class InnerHits
 	[JsonInclude, JsonPropertyName("explain")]
 	public bool? Explain { get; set; }
 	[JsonInclude, JsonPropertyName("fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? Fields { get; set; }
 
 	/// <summary>
@@ -73,6 +74,7 @@ public sealed partial class InnerHits
 	[JsonInclude, JsonPropertyName("_source")]
 	public Elastic.Clients.Elasticsearch.Serverless.Core.Search.SourceConfig? Source { get; set; }
 	[JsonInclude, JsonPropertyName("stored_fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? StoredFields { get; set; }
 	[JsonInclude, JsonPropertyName("track_scores")]
 	public bool? TrackScores { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Enrich/EnrichPolicy.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Enrich/EnrichPolicy.g.cs
index e45b8e52cb3..fdac64dac40 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Enrich/EnrichPolicy.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Enrich/EnrichPolicy.g.cs
@@ -32,6 +32,7 @@ public sealed partial class EnrichPolicy
 	[JsonInclude, JsonPropertyName("elasticsearch_version")]
 	public string? ElasticsearchVersion { get; set; }
 	[JsonInclude, JsonPropertyName("enrich_fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields EnrichFields { get; set; }
 	[JsonInclude, JsonPropertyName("indices")]
 	public Elastic.Clients.Elasticsearch.Serverless.Indices Indices { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/IndexManagement/IndexSegmentSort.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/IndexManagement/IndexSegmentSort.g.cs
index f49fefd83c8..3aedc9a4378 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/IndexManagement/IndexSegmentSort.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/IndexManagement/IndexSegmentSort.g.cs
@@ -30,6 +30,7 @@ namespace Elastic.Clients.Elasticsearch.Serverless.IndexManagement;
 public sealed partial class IndexSegmentSort
 {
 	[JsonInclude, JsonPropertyName("field")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? Field { get; set; }
 	[JsonInclude, JsonPropertyName("missing")]
 	[SingleOrManyCollectionConverter(typeof(Elastic.Clients.Elasticsearch.Serverless.IndexManagement.SegmentSortMissing))]
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Ingest/CsvProcessor.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Ingest/CsvProcessor.g.cs
index 8ddcf0ab1a1..5f4db76a4f1 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Ingest/CsvProcessor.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Ingest/CsvProcessor.g.cs
@@ -93,6 +93,7 @@ public sealed partial class CsvProcessor
 	/// <para>The array of fields to assign extracted values to.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("target_fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields TargetFields { get; set; }
 
 	/// <summary>
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Ingest/RemoveProcessor.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Ingest/RemoveProcessor.g.cs
index 89cc1481c37..62a47999ca0 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Ingest/RemoveProcessor.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Ingest/RemoveProcessor.g.cs
@@ -39,6 +39,7 @@ public sealed partial class RemoveProcessor
 	/// <para>Fields to be removed. Supports template snippets.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("field")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields Field { get; set; }
 
 	/// <summary>
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/MachineLearning/AnalysisConfig.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/MachineLearning/AnalysisConfig.g.cs
index 9f96a792b7c..de62c2c7289 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/MachineLearning/AnalysisConfig.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/MachineLearning/AnalysisConfig.g.cs
@@ -63,7 +63,8 @@ public sealed partial class AnalysisConfig
 	/// <para>A comma separated list of influencer field names. Typically these can be the by, over, or partition fields that are used in the detector configuration. You might also want to use a field name that is not specifically named in a detector, but is available as part of the input data. When you use multiple detectors, the use of influencers is recommended as it aggregates results for each influencer entity.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("influencers")]
-	public ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? Influencers { get; set; }
+	[JsonConverter(typeof(FieldsConverter))]
+	public Elastic.Clients.Elasticsearch.Serverless.Fields? Influencers { get; set; }
 
 	/// <summary>
 	/// <para>The size of the window in which to expect data that is out of time order. If you specify a non-zero value, it must be greater than or equal to one second. NOTE: Latency is applicable only when you send data by using the post data API.</para>
@@ -112,7 +113,7 @@ public AnalysisConfigDescriptor() : base()
 	private Elastic.Clients.Elasticsearch.Serverless.MachineLearning.DetectorDescriptor<TDocument> DetectorsDescriptor { get; set; }
 	private Action<Elastic.Clients.Elasticsearch.Serverless.MachineLearning.DetectorDescriptor<TDocument>> DetectorsDescriptorAction { get; set; }
 	private Action<Elastic.Clients.Elasticsearch.Serverless.MachineLearning.DetectorDescriptor<TDocument>>[] DetectorsDescriptorActions { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? InfluencersValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Serverless.Fields? InfluencersValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Serverless.Duration? LatencyValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Serverless.Duration? ModelPruneWindowValue { get; set; }
 	private bool? MultivariateByFieldsValue { get; set; }
@@ -217,7 +218,7 @@ public AnalysisConfigDescriptor<TDocument> Detectors(params Action<Elastic.Clien
 	/// <summary>
 	/// <para>A comma separated list of influencer field names. Typically these can be the by, over, or partition fields that are used in the detector configuration. You might also want to use a field name that is not specifically named in a detector, but is available as part of the input data. When you use multiple detectors, the use of influencers is recommended as it aggregates results for each influencer entity.</para>
 	/// </summary>
-	public AnalysisConfigDescriptor<TDocument> Influencers(ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? influencers)
+	public AnalysisConfigDescriptor<TDocument> Influencers(Elastic.Clients.Elasticsearch.Serverless.Fields? influencers)
 	{
 		InfluencersValue = influencers;
 		return Self;
@@ -428,7 +429,7 @@ public AnalysisConfigDescriptor() : base()
 	private Elastic.Clients.Elasticsearch.Serverless.MachineLearning.DetectorDescriptor DetectorsDescriptor { get; set; }
 	private Action<Elastic.Clients.Elasticsearch.Serverless.MachineLearning.DetectorDescriptor> DetectorsDescriptorAction { get; set; }
 	private Action<Elastic.Clients.Elasticsearch.Serverless.MachineLearning.DetectorDescriptor>[] DetectorsDescriptorActions { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? InfluencersValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Serverless.Fields? InfluencersValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Serverless.Duration? LatencyValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Serverless.Duration? ModelPruneWindowValue { get; set; }
 	private bool? MultivariateByFieldsValue { get; set; }
@@ -533,7 +534,7 @@ public AnalysisConfigDescriptor Detectors(params Action<Elastic.Clients.Elastics
 	/// <summary>
 	/// <para>A comma separated list of influencer field names. Typically these can be the by, over, or partition fields that are used in the detector configuration. You might also want to use a field name that is not specifically named in a detector, but is available as part of the input data. When you use multiple detectors, the use of influencers is recommended as it aggregates results for each influencer entity.</para>
 	/// </summary>
-	public AnalysisConfigDescriptor Influencers(ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? influencers)
+	public AnalysisConfigDescriptor Influencers(Elastic.Clients.Elasticsearch.Serverless.Fields? influencers)
 	{
 		InfluencersValue = influencers;
 		return Self;
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/BinaryProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/BinaryProperty.g.cs
index ed41e2bcc9b..091b905814b 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/BinaryProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/BinaryProperty.g.cs
@@ -30,6 +30,7 @@ namespace Elastic.Clients.Elasticsearch.Serverless.Mapping;
 public sealed partial class BinaryProperty : IProperty
 {
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/BooleanProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/BooleanProperty.g.cs
index a23ba6f9454..d495e04aef1 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/BooleanProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/BooleanProperty.g.cs
@@ -32,6 +32,7 @@ public sealed partial class BooleanProperty : IProperty
 	[JsonInclude, JsonPropertyName("boost")]
 	public double? Boost { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/ByteNumberProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/ByteNumberProperty.g.cs
index b96f2ed5ed1..cf9a3a88fa4 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/ByteNumberProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/ByteNumberProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class ByteNumberProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/CompletionProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/CompletionProperty.g.cs
index 4bea0625fec..b2e90a7c21e 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/CompletionProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/CompletionProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class CompletionProperty : IProperty
 	[JsonInclude, JsonPropertyName("contexts")]
 	public ICollection<Elastic.Clients.Elasticsearch.Serverless.Mapping.SuggestContext>? Contexts { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DateNanosProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DateNanosProperty.g.cs
index ab928e5f9b0..33c02d5c08f 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DateNanosProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DateNanosProperty.g.cs
@@ -32,6 +32,7 @@ public sealed partial class DateNanosProperty : IProperty
 	[JsonInclude, JsonPropertyName("boost")]
 	public double? Boost { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DateProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DateProperty.g.cs
index b990974fefc..a656dfab13a 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DateProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DateProperty.g.cs
@@ -32,6 +32,7 @@ public sealed partial class DateProperty : IProperty
 	[JsonInclude, JsonPropertyName("boost")]
 	public double? Boost { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DateRangeProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DateRangeProperty.g.cs
index b9638750fd7..f4962b51522 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DateRangeProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DateRangeProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class DateRangeProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DoubleNumberProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DoubleNumberProperty.g.cs
index d470ee44fbc..049755248e9 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DoubleNumberProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DoubleNumberProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class DoubleNumberProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DoubleRangeProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DoubleRangeProperty.g.cs
index b93079c7bcf..43547a103e1 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DoubleRangeProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DoubleRangeProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class DoubleRangeProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DynamicProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DynamicProperty.g.cs
index 0e0eedba3b8..423ce47c30f 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DynamicProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/DynamicProperty.g.cs
@@ -36,6 +36,7 @@ public sealed partial class DynamicProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/FloatNumberProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/FloatNumberProperty.g.cs
index 4f6f27541d6..dcc01e463be 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/FloatNumberProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/FloatNumberProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class FloatNumberProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/FloatRangeProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/FloatRangeProperty.g.cs
index 6bbe4514456..b44f492c902 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/FloatRangeProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/FloatRangeProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class FloatRangeProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/GeoPointProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/GeoPointProperty.g.cs
index 719eeac01c0..830c46a4954 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/GeoPointProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/GeoPointProperty.g.cs
@@ -30,6 +30,7 @@ namespace Elastic.Clients.Elasticsearch.Serverless.Mapping;
 public sealed partial class GeoPointProperty : IProperty
 {
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/GeoShapeProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/GeoShapeProperty.g.cs
index 9f6ca47cd13..11fce74d369 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/GeoShapeProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/GeoShapeProperty.g.cs
@@ -36,6 +36,7 @@ public sealed partial class GeoShapeProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/HalfFloatNumberProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/HalfFloatNumberProperty.g.cs
index 1c421d8b924..e0c91cabb43 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/HalfFloatNumberProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/HalfFloatNumberProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class HalfFloatNumberProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/IntegerNumberProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/IntegerNumberProperty.g.cs
index 7deaf3c6e57..f4b0c2bc36c 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/IntegerNumberProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/IntegerNumberProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class IntegerNumberProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/IntegerRangeProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/IntegerRangeProperty.g.cs
index 5d6c6151f82..1a8bed24b43 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/IntegerRangeProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/IntegerRangeProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class IntegerRangeProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/IpProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/IpProperty.g.cs
index 544450edd36..f73237663f4 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/IpProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/IpProperty.g.cs
@@ -32,6 +32,7 @@ public sealed partial class IpProperty : IProperty
 	[JsonInclude, JsonPropertyName("boost")]
 	public double? Boost { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/IpRangeProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/IpRangeProperty.g.cs
index 78c3cfb55c3..37bb9fba63d 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/IpRangeProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/IpRangeProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class IpRangeProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/KeywordProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/KeywordProperty.g.cs
index acade25c01f..861cd3e4a79 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/KeywordProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/KeywordProperty.g.cs
@@ -32,6 +32,7 @@ public sealed partial class KeywordProperty : IProperty
 	[JsonInclude, JsonPropertyName("boost")]
 	public double? Boost { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/LongNumberProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/LongNumberProperty.g.cs
index 08a6ea93f51..11bad1da35c 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/LongNumberProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/LongNumberProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class LongNumberProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/LongRangeProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/LongRangeProperty.g.cs
index 26f0c4ef9b1..fd6273d2097 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/LongRangeProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/LongRangeProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class LongRangeProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/MatchOnlyTextProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/MatchOnlyTextProperty.g.cs
index 27446e05fc8..655261d6db3 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/MatchOnlyTextProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/MatchOnlyTextProperty.g.cs
@@ -36,6 +36,7 @@ public sealed partial class MatchOnlyTextProperty : IProperty
 	/// <para>Allows you to copy the values of multiple fields into a group<br/>field, which can then be queried as a single field.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 
 	/// <summary>
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/Murmur3HashProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/Murmur3HashProperty.g.cs
index bd90399b3ca..0a03e6e2d8a 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/Murmur3HashProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/Murmur3HashProperty.g.cs
@@ -30,6 +30,7 @@ namespace Elastic.Clients.Elasticsearch.Serverless.Mapping;
 public sealed partial class Murmur3HashProperty : IProperty
 {
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/NestedProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/NestedProperty.g.cs
index dc2431c6926..f41649bf449 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/NestedProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/NestedProperty.g.cs
@@ -30,6 +30,7 @@ namespace Elastic.Clients.Elasticsearch.Serverless.Mapping;
 public sealed partial class NestedProperty : IProperty
 {
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("dynamic")]
 	public Elastic.Clients.Elasticsearch.Serverless.Mapping.DynamicMapping? Dynamic { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/ObjectProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/ObjectProperty.g.cs
index 3ae6b25843f..c0e6da2811d 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/ObjectProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/ObjectProperty.g.cs
@@ -30,6 +30,7 @@ namespace Elastic.Clients.Elasticsearch.Serverless.Mapping;
 public sealed partial class ObjectProperty : IProperty
 {
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("dynamic")]
 	public Elastic.Clients.Elasticsearch.Serverless.Mapping.DynamicMapping? Dynamic { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/PointProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/PointProperty.g.cs
index f2fdcf01fe5..9180209d5d1 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/PointProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/PointProperty.g.cs
@@ -30,6 +30,7 @@ namespace Elastic.Clients.Elasticsearch.Serverless.Mapping;
 public sealed partial class PointProperty : IProperty
 {
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/ScaledFloatNumberProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/ScaledFloatNumberProperty.g.cs
index 3fa348209cf..e058dd3ff91 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/ScaledFloatNumberProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/ScaledFloatNumberProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class ScaledFloatNumberProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/SearchAsYouTypeProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/SearchAsYouTypeProperty.g.cs
index 91107cafec2..5159255d910 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/SearchAsYouTypeProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/SearchAsYouTypeProperty.g.cs
@@ -32,6 +32,7 @@ public sealed partial class SearchAsYouTypeProperty : IProperty
 	[JsonInclude, JsonPropertyName("analyzer")]
 	public string? Analyzer { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("dynamic")]
 	public Elastic.Clients.Elasticsearch.Serverless.Mapping.DynamicMapping? Dynamic { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/ShapeProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/ShapeProperty.g.cs
index 89aa1420dcc..d0252535420 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/ShapeProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/ShapeProperty.g.cs
@@ -36,6 +36,7 @@ public sealed partial class ShapeProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/ShortNumberProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/ShortNumberProperty.g.cs
index 07d6c0209de..de15f8cc2bd 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/ShortNumberProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/ShortNumberProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class ShortNumberProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/TextProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/TextProperty.g.cs
index e1e72f9938a..58ef2daed66 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/TextProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/TextProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class TextProperty : IProperty
 	[JsonInclude, JsonPropertyName("boost")]
 	public double? Boost { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("dynamic")]
 	public Elastic.Clients.Elasticsearch.Serverless.Mapping.DynamicMapping? Dynamic { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/TokenCountProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/TokenCountProperty.g.cs
index 949debd9a39..3cd3073e5a5 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/TokenCountProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/TokenCountProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class TokenCountProperty : IProperty
 	[JsonInclude, JsonPropertyName("boost")]
 	public double? Boost { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/UnsignedLongNumberProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/UnsignedLongNumberProperty.g.cs
index 3f9bec78133..0d15d5f9328 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/UnsignedLongNumberProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/UnsignedLongNumberProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class UnsignedLongNumberProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/VersionProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/VersionProperty.g.cs
index 20c3feeb030..9a17f9d0ada 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/VersionProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/VersionProperty.g.cs
@@ -30,6 +30,7 @@ namespace Elastic.Clients.Elasticsearch.Serverless.Mapping;
 public sealed partial class VersionProperty : IProperty
 {
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/WildcardProperty.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/WildcardProperty.g.cs
index d9c6ecce7c0..bd1e13c40ef 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/WildcardProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/Mapping/WildcardProperty.g.cs
@@ -30,6 +30,7 @@ namespace Elastic.Clients.Elasticsearch.Serverless.Mapping;
 public sealed partial class WildcardProperty : IProperty
 {
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/CombinedFieldsQuery.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/CombinedFieldsQuery.g.cs
index 42a3b153ea2..00c946f3058 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/CombinedFieldsQuery.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/CombinedFieldsQuery.g.cs
@@ -45,7 +45,8 @@ public sealed partial class CombinedFieldsQuery
 	/// <para>List of fields to search. Field wildcard patterns are allowed. Only `text` fields are supported, and they must all have the same search `analyzer`.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("fields")]
-	public ICollection<Elastic.Clients.Elasticsearch.Serverless.Field> Fields { get; set; }
+	[JsonConverter(typeof(FieldsConverter))]
+	public Elastic.Clients.Elasticsearch.Serverless.Fields Fields { get; set; }
 
 	/// <summary>
 	/// <para>Minimum number of clauses that must match for a document to be returned.</para>
@@ -86,7 +87,7 @@ public CombinedFieldsQueryDescriptor() : base()
 
 	private bool? AutoGenerateSynonymsPhraseQueryValue { get; set; }
 	private float? BoostValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Serverless.Field> FieldsValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Serverless.Fields FieldsValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Serverless.MinimumShouldMatch? MinimumShouldMatchValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Serverless.QueryDsl.CombinedFieldsOperator? OperatorValue { get; set; }
 	private string QueryValue { get; set; }
@@ -114,7 +115,7 @@ public CombinedFieldsQueryDescriptor<TDocument> Boost(float? boost)
 	/// <summary>
 	/// <para>List of fields to search. Field wildcard patterns are allowed. Only `text` fields are supported, and they must all have the same search `analyzer`.</para>
 	/// </summary>
-	public CombinedFieldsQueryDescriptor<TDocument> Fields(ICollection<Elastic.Clients.Elasticsearch.Serverless.Field> fields)
+	public CombinedFieldsQueryDescriptor<TDocument> Fields(Elastic.Clients.Elasticsearch.Serverless.Fields fields)
 	{
 		FieldsValue = fields;
 		return Self;
@@ -219,7 +220,7 @@ public CombinedFieldsQueryDescriptor() : base()
 
 	private bool? AutoGenerateSynonymsPhraseQueryValue { get; set; }
 	private float? BoostValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Serverless.Field> FieldsValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Serverless.Fields FieldsValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Serverless.MinimumShouldMatch? MinimumShouldMatchValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Serverless.QueryDsl.CombinedFieldsOperator? OperatorValue { get; set; }
 	private string QueryValue { get; set; }
@@ -247,7 +248,7 @@ public CombinedFieldsQueryDescriptor Boost(float? boost)
 	/// <summary>
 	/// <para>List of fields to search. Field wildcard patterns are allowed. Only `text` fields are supported, and they must all have the same search `analyzer`.</para>
 	/// </summary>
-	public CombinedFieldsQueryDescriptor Fields(ICollection<Elastic.Clients.Elasticsearch.Serverless.Field> fields)
+	public CombinedFieldsQueryDescriptor Fields(Elastic.Clients.Elasticsearch.Serverless.Fields fields)
 	{
 		FieldsValue = fields;
 		return Self;
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/LikeDocument.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/LikeDocument.g.cs
index 4b60fca4ae1..356de3ae9c2 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/LikeDocument.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/LikeDocument.g.cs
@@ -35,7 +35,8 @@ public sealed partial class LikeDocument
 	[JsonInclude, JsonPropertyName("doc")]
 	public object? Doc { get; set; }
 	[JsonInclude, JsonPropertyName("fields")]
-	public ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? Fields { get; set; }
+	[JsonConverter(typeof(FieldsConverter))]
+	public Elastic.Clients.Elasticsearch.Serverless.Fields? Fields { get; set; }
 
 	/// <summary>
 	/// <para>ID of a document.</para>
@@ -67,7 +68,7 @@ public LikeDocumentDescriptor() : base()
 	}
 
 	private object? DocValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? FieldsValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Serverless.Fields? FieldsValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Serverless.Id? IdValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Serverless.IndexName? IndexValue { get; set; }
 	private IDictionary<Elastic.Clients.Elasticsearch.Serverless.Field, string>? PerFieldAnalyzerValue { get; set; }
@@ -84,7 +85,7 @@ public LikeDocumentDescriptor<TDocument> Doc(object? doc)
 		return Self;
 	}
 
-	public LikeDocumentDescriptor<TDocument> Fields(ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? fields)
+	public LikeDocumentDescriptor<TDocument> Fields(Elastic.Clients.Elasticsearch.Serverless.Fields? fields)
 	{
 		FieldsValue = fields;
 		return Self;
@@ -196,7 +197,7 @@ public LikeDocumentDescriptor() : base()
 	}
 
 	private object? DocValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? FieldsValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Serverless.Fields? FieldsValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Serverless.Id? IdValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Serverless.IndexName? IndexValue { get; set; }
 	private IDictionary<Elastic.Clients.Elasticsearch.Serverless.Field, string>? PerFieldAnalyzerValue { get; set; }
@@ -213,7 +214,7 @@ public LikeDocumentDescriptor Doc(object? doc)
 		return Self;
 	}
 
-	public LikeDocumentDescriptor Fields(ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? fields)
+	public LikeDocumentDescriptor Fields(Elastic.Clients.Elasticsearch.Serverless.Fields? fields)
 	{
 		FieldsValue = fields;
 		return Self;
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/MoreLikeThisQuery.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/MoreLikeThisQuery.g.cs
index 6b40066fa50..6e9d0cde6dd 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/MoreLikeThisQuery.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/MoreLikeThisQuery.g.cs
@@ -57,7 +57,8 @@ public sealed partial class MoreLikeThisQuery
 	/// <para>A list of fields to fetch and analyze the text from.<br/>Defaults to the `index.query.default_field` index setting, which has a default value of `*`.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("fields")]
-	public ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? Fields { get; set; }
+	[JsonConverter(typeof(FieldsConverter))]
+	public Elastic.Clients.Elasticsearch.Serverless.Fields? Fields { get; set; }
 
 	/// <summary>
 	/// <para>Specifies whether the input documents should also be included in the search results returned.</para>
@@ -157,7 +158,7 @@ public MoreLikeThisQueryDescriptor() : base()
 	private float? BoostValue { get; set; }
 	private double? BoostTermsValue { get; set; }
 	private bool? FailOnUnsupportedFieldValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? FieldsValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Serverless.Fields? FieldsValue { get; set; }
 	private bool? IncludeValue { get; set; }
 	private ICollection<Elastic.Clients.Elasticsearch.Serverless.QueryDsl.Like> LikeValue { get; set; }
 	private int? MaxDocFreqValue { get; set; }
@@ -214,7 +215,7 @@ public MoreLikeThisQueryDescriptor<TDocument> FailOnUnsupportedField(bool? failO
 	/// <summary>
 	/// <para>A list of fields to fetch and analyze the text from.<br/>Defaults to the `index.query.default_field` index setting, which has a default value of `*`.</para>
 	/// </summary>
-	public MoreLikeThisQueryDescriptor<TDocument> Fields(ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? fields)
+	public MoreLikeThisQueryDescriptor<TDocument> Fields(Elastic.Clients.Elasticsearch.Serverless.Fields? fields)
 	{
 		FieldsValue = fields;
 		return Self;
@@ -493,7 +494,7 @@ public MoreLikeThisQueryDescriptor() : base()
 	private float? BoostValue { get; set; }
 	private double? BoostTermsValue { get; set; }
 	private bool? FailOnUnsupportedFieldValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? FieldsValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Serverless.Fields? FieldsValue { get; set; }
 	private bool? IncludeValue { get; set; }
 	private ICollection<Elastic.Clients.Elasticsearch.Serverless.QueryDsl.Like> LikeValue { get; set; }
 	private int? MaxDocFreqValue { get; set; }
@@ -550,7 +551,7 @@ public MoreLikeThisQueryDescriptor FailOnUnsupportedField(bool? failOnUnsupporte
 	/// <summary>
 	/// <para>A list of fields to fetch and analyze the text from.<br/>Defaults to the `index.query.default_field` index setting, which has a default value of `*`.</para>
 	/// </summary>
-	public MoreLikeThisQueryDescriptor Fields(ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? fields)
+	public MoreLikeThisQueryDescriptor Fields(Elastic.Clients.Elasticsearch.Serverless.Fields? fields)
 	{
 		FieldsValue = fields;
 		return Self;
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/MultiMatchQuery.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/MultiMatchQuery.g.cs
index f196efdf9bf..812d0b8c2a2 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/MultiMatchQuery.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/MultiMatchQuery.g.cs
@@ -51,6 +51,7 @@ public sealed partial class MultiMatchQuery
 	/// <para>The fields to be queried.<br/>Defaults to the `index.query.default_field` index settings, which in turn defaults to `*`.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Serverless.Fields? Fields { get; set; }
 
 	/// <summary>
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/QueryStringQuery.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/QueryStringQuery.g.cs
index 9a986c29b07..32bdc385b11 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/QueryStringQuery.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/QueryStringQuery.g.cs
@@ -83,7 +83,8 @@ public sealed partial class QueryStringQuery
 	/// <para>Array of fields to search. Supports wildcards (`*`).</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("fields")]
-	public ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? Fields { get; set; }
+	[JsonConverter(typeof(FieldsConverter))]
+	public Elastic.Clients.Elasticsearch.Serverless.Fields? Fields { get; set; }
 
 	/// <summary>
 	/// <para>Maximum edit distance allowed for fuzzy matching.</para>
@@ -203,7 +204,7 @@ public QueryStringQueryDescriptor() : base()
 	private Elastic.Clients.Elasticsearch.Serverless.QueryDsl.Operator? DefaultOperatorValue { get; set; }
 	private bool? EnablePositionIncrementsValue { get; set; }
 	private bool? EscapeValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? FieldsValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Serverless.Fields? FieldsValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Serverless.Fuzziness? FuzzinessValue { get; set; }
 	private int? FuzzyMaxExpansionsValue { get; set; }
 	private int? FuzzyPrefixLengthValue { get; set; }
@@ -321,7 +322,7 @@ public QueryStringQueryDescriptor<TDocument> Escape(bool? escape = true)
 	/// <summary>
 	/// <para>Array of fields to search. Supports wildcards (`*`).</para>
 	/// </summary>
-	public QueryStringQueryDescriptor<TDocument> Fields(ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? fields)
+	public QueryStringQueryDescriptor<TDocument> Fields(Elastic.Clients.Elasticsearch.Serverless.Fields? fields)
 	{
 		FieldsValue = fields;
 		return Self;
@@ -659,7 +660,7 @@ public QueryStringQueryDescriptor() : base()
 	private Elastic.Clients.Elasticsearch.Serverless.QueryDsl.Operator? DefaultOperatorValue { get; set; }
 	private bool? EnablePositionIncrementsValue { get; set; }
 	private bool? EscapeValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? FieldsValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Serverless.Fields? FieldsValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Serverless.Fuzziness? FuzzinessValue { get; set; }
 	private int? FuzzyMaxExpansionsValue { get; set; }
 	private int? FuzzyPrefixLengthValue { get; set; }
@@ -777,7 +778,7 @@ public QueryStringQueryDescriptor Escape(bool? escape = true)
 	/// <summary>
 	/// <para>Array of fields to search. Supports wildcards (`*`).</para>
 	/// </summary>
-	public QueryStringQueryDescriptor Fields(ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? fields)
+	public QueryStringQueryDescriptor Fields(Elastic.Clients.Elasticsearch.Serverless.Fields? fields)
 	{
 		FieldsValue = fields;
 		return Self;
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/SimpleQueryStringQuery.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/SimpleQueryStringQuery.g.cs
index 1077d028c3a..5c8945de48d 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/SimpleQueryStringQuery.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/QueryDsl/SimpleQueryStringQuery.g.cs
@@ -63,7 +63,8 @@ public sealed partial class SimpleQueryStringQuery
 	/// <para>Array of fields you wish to search.<br/>Accepts wildcard expressions.<br/>You also can boost relevance scores for matches to particular fields using a caret (`^`) notation.<br/>Defaults to the `index.query.default_field index` setting, which has a default value of `*`.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("fields")]
-	public ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? Fields { get; set; }
+	[JsonConverter(typeof(FieldsConverter))]
+	public Elastic.Clients.Elasticsearch.Serverless.Fields? Fields { get; set; }
 
 	/// <summary>
 	/// <para>List of enabled operators for the simple query string syntax.</para>
@@ -131,7 +132,7 @@ public SimpleQueryStringQueryDescriptor() : base()
 	private bool? AutoGenerateSynonymsPhraseQueryValue { get; set; }
 	private float? BoostValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Serverless.QueryDsl.Operator? DefaultOperatorValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? FieldsValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Serverless.Fields? FieldsValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Serverless.QueryDsl.SimpleQueryStringFlag? FlagsValue { get; set; }
 	private int? FuzzyMaxExpansionsValue { get; set; }
 	private int? FuzzyPrefixLengthValue { get; set; }
@@ -190,7 +191,7 @@ public SimpleQueryStringQueryDescriptor<TDocument> DefaultOperator(Elastic.Clien
 	/// <summary>
 	/// <para>Array of fields you wish to search.<br/>Accepts wildcard expressions.<br/>You also can boost relevance scores for matches to particular fields using a caret (`^`) notation.<br/>Defaults to the `index.query.default_field index` setting, which has a default value of `*`.</para>
 	/// </summary>
-	public SimpleQueryStringQueryDescriptor<TDocument> Fields(ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? fields)
+	public SimpleQueryStringQueryDescriptor<TDocument> Fields(Elastic.Clients.Elasticsearch.Serverless.Fields? fields)
 	{
 		FieldsValue = fields;
 		return Self;
@@ -380,7 +381,7 @@ public SimpleQueryStringQueryDescriptor() : base()
 	private bool? AutoGenerateSynonymsPhraseQueryValue { get; set; }
 	private float? BoostValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Serverless.QueryDsl.Operator? DefaultOperatorValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? FieldsValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Serverless.Fields? FieldsValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Serverless.QueryDsl.SimpleQueryStringFlag? FlagsValue { get; set; }
 	private int? FuzzyMaxExpansionsValue { get; set; }
 	private int? FuzzyPrefixLengthValue { get; set; }
@@ -439,7 +440,7 @@ public SimpleQueryStringQueryDescriptor DefaultOperator(Elastic.Clients.Elastics
 	/// <summary>
 	/// <para>Array of fields you wish to search.<br/>Accepts wildcard expressions.<br/>You also can boost relevance scores for matches to particular fields using a caret (`^`) notation.<br/>Defaults to the `index.query.default_field index` setting, which has a default value of `*`.</para>
 	/// </summary>
-	public SimpleQueryStringQueryDescriptor Fields(ICollection<Elastic.Clients.Elasticsearch.Serverless.Field>? fields)
+	public SimpleQueryStringQueryDescriptor Fields(Elastic.Clients.Elasticsearch.Serverless.Fields? fields)
 	{
 		FieldsValue = fields;
 		return Self;
diff --git a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/TransformManagement/Latest.g.cs b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/TransformManagement/Latest.g.cs
index bbda8604b21..8e09a0d9b45 100644
--- a/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/TransformManagement/Latest.g.cs
+++ b/src/Elastic.Clients.Elasticsearch.Serverless/_Generated/Types/TransformManagement/Latest.g.cs
@@ -39,7 +39,8 @@ public sealed partial class Latest
 	/// <para>Specifies an array of one or more fields that are used to group the data.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("unique_key")]
-	public ICollection<Elastic.Clients.Elasticsearch.Serverless.Field> UniqueKey { get; set; }
+	[JsonConverter(typeof(FieldsConverter))]
+	public Elastic.Clients.Elasticsearch.Serverless.Fields UniqueKey { get; set; }
 }
 
 public sealed partial class LatestDescriptor<TDocument> : SerializableDescriptor<LatestDescriptor<TDocument>>
@@ -51,7 +52,7 @@ public LatestDescriptor() : base()
 	}
 
 	private Elastic.Clients.Elasticsearch.Serverless.Field SortValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Serverless.Field> UniqueKeyValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Serverless.Fields UniqueKeyValue { get; set; }
 
 	/// <summary>
 	/// <para>Specifies the date field that is used to identify the latest documents.</para>
@@ -83,7 +84,7 @@ public LatestDescriptor<TDocument> Sort(Expression<Func<TDocument, object>> sort
 	/// <summary>
 	/// <para>Specifies an array of one or more fields that are used to group the data.</para>
 	/// </summary>
-	public LatestDescriptor<TDocument> UniqueKey(ICollection<Elastic.Clients.Elasticsearch.Serverless.Field> uniqueKey)
+	public LatestDescriptor<TDocument> UniqueKey(Elastic.Clients.Elasticsearch.Serverless.Fields uniqueKey)
 	{
 		UniqueKeyValue = uniqueKey;
 		return Self;
@@ -109,7 +110,7 @@ public LatestDescriptor() : base()
 	}
 
 	private Elastic.Clients.Elasticsearch.Serverless.Field SortValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Serverless.Field> UniqueKeyValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Serverless.Fields UniqueKeyValue { get; set; }
 
 	/// <summary>
 	/// <para>Specifies the date field that is used to identify the latest documents.</para>
@@ -141,7 +142,7 @@ public LatestDescriptor Sort<TDocument>(Expression<Func<TDocument, object>> sort
 	/// <summary>
 	/// <para>Specifies an array of one or more fields that are used to group the data.</para>
 	/// </summary>
-	public LatestDescriptor UniqueKey(ICollection<Elastic.Clients.Elasticsearch.Serverless.Field> uniqueKey)
+	public LatestDescriptor UniqueKey(Elastic.Clients.Elasticsearch.Serverless.Fields uniqueKey)
 	{
 		UniqueKeyValue = uniqueKey;
 		return Self;
diff --git a/src/Elastic.Clients.Elasticsearch.Shared/Core/Infer/Fields/Fields.cs b/src/Elastic.Clients.Elasticsearch.Shared/Core/Infer/Fields/Fields.cs
index debe5562826..dec3a645ad7 100644
--- a/src/Elastic.Clients.Elasticsearch.Shared/Core/Infer/Fields/Fields.cs
+++ b/src/Elastic.Clients.Elasticsearch.Shared/Core/Infer/Fields/Fields.cs
@@ -10,7 +10,6 @@
 using System.Linq.Expressions;
 using System.Reflection;
 using System.Text.Json;
-using System.Text.Json.Serialization;
 using Elastic.Transport;
 
 #if ELASTICSEARCH_SERVERLESS
@@ -19,7 +18,6 @@ namespace Elastic.Clients.Elasticsearch.Serverless;
 namespace Elastic.Clients.Elasticsearch;
 #endif
 
-[JsonConverter(typeof(FieldsConverter))]
 [DebuggerDisplay("{DebugDisplay,nq}")]
 public sealed class Fields : IUrlParameter, IEnumerable<Field>, IEquatable<Fields>
 {
diff --git a/src/Elastic.Clients.Elasticsearch.Shared/Core/Infer/Fields/FieldsConverter.cs b/src/Elastic.Clients.Elasticsearch.Shared/Core/Infer/Fields/FieldsConverter.cs
index 1788f8d1e1a..d7a9044dabf 100644
--- a/src/Elastic.Clients.Elasticsearch.Shared/Core/Infer/Fields/FieldsConverter.cs
+++ b/src/Elastic.Clients.Elasticsearch.Shared/Core/Infer/Fields/FieldsConverter.cs
@@ -53,3 +53,58 @@ public override void Write(Utf8JsonWriter writer, Fields value, JsonSerializerOp
 		writer.WriteEndArray();
 	}
 }
+
+internal sealed class SingleOrManyFieldsConverter : JsonConverter<Fields>
+{
+	public override Fields? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+	{
+		if (reader.TokenType == JsonTokenType.String)
+		{
+			Fields fields = reader.GetString();
+			return fields;
+		}
+
+		if (reader.TokenType == JsonTokenType.StartArray)
+		{
+			var fields = new List<Field>();
+			while (reader.Read() && reader.TokenType != JsonTokenType.EndArray)
+			{
+				var field = JsonSerializer.Deserialize<Field>(ref reader, options);
+				fields.Add(field);
+			}
+			return new Fields(fields);
+		}
+
+		reader.Read();
+		return null;
+	}
+
+	public override void Write(Utf8JsonWriter writer, Fields value, JsonSerializerOptions options)
+	{
+		if (value is null)
+		{
+			writer.WriteNullValue();
+			return;
+		}
+
+		//if (value.ListOfFields.Count == 0)
+		//{
+		//	writer.WriteStartObject();
+		//	writer.WriteEndObject();
+		//	return;
+		//}
+
+		if (value.ListOfFields.Count == 1)
+		{
+			JsonSerializer.Serialize(writer, value.ListOfFields[0], options);
+			return;
+		}
+
+		writer.WriteStartArray();
+		foreach (var field in value.ListOfFields)
+		{
+			JsonSerializer.Serialize(writer, field, options);
+		}
+		writer.WriteEndArray();
+	}
+}
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Api/AsyncSearch/SubmitAsyncSearchRequest.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Api/AsyncSearch/SubmitAsyncSearchRequest.g.cs
index b7dab5cb5e9..30df4097441 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Api/AsyncSearch/SubmitAsyncSearchRequest.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Api/AsyncSearch/SubmitAsyncSearchRequest.g.cs
@@ -911,6 +911,7 @@ public SubmitAsyncSearchRequest(Elastic.Clients.Elasticsearch.Indices? indices)
 	/// <para>List of stored fields to return as part of a hit. If no fields are specified,<br/>no stored fields are included in the response. If this field is specified, the _source<br/>parameter defaults to false. You can pass _source: true to return both source fields<br/>and stored fields in the search response.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("stored_fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? StoredFields { get; set; }
 	[JsonInclude, JsonPropertyName("suggest")]
 	public Elastic.Clients.Elasticsearch.Core.Search.Suggester? Suggest { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Api/FieldCapsRequest.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Api/FieldCapsRequest.g.cs
index fa03c8f9539..a28c466e09c 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Api/FieldCapsRequest.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Api/FieldCapsRequest.g.cs
@@ -134,6 +134,7 @@ public FieldCapsRequest(Elastic.Clients.Elasticsearch.Indices? indices) : base(r
 	/// <para>List of fields to retrieve capabilities for. Wildcard (`*`) expressions are supported.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? Fields { get; set; }
 
 	/// <summary>
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Api/SearchMvtRequest.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Api/SearchMvtRequest.g.cs
index 607e8d37d05..31afdead96d 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Api/SearchMvtRequest.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Api/SearchMvtRequest.g.cs
@@ -79,6 +79,7 @@ public SearchMvtRequest(Elastic.Clients.Elasticsearch.Indices indices, Elastic.C
 	/// <para>Fields to return in the `hits` layer. Supports wildcards (`*`).<br/>This parameter does not support fields with array values. Fields with array<br/>values may return inconsistent results.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? Fields { get; set; }
 
 	/// <summary>
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Api/SearchRequest.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Api/SearchRequest.g.cs
index ae317919acc..c078f55aa7b 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Api/SearchRequest.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Api/SearchRequest.g.cs
@@ -956,6 +956,7 @@ public SearchRequest(Elastic.Clients.Elasticsearch.Indices? indices) : base(r =>
 	/// <para>List of stored fields to return as part of a hit.<br/>If no fields are specified, no stored fields are included in the response.<br/>If this field is specified, the `_source` parameter defaults to `false`.<br/>You can pass `_source: true` to return both source fields and stored fields in the search response.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("stored_fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? StoredFields { get; set; }
 
 	/// <summary>
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Aggregations/MatrixStatsAggregation.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Aggregations/MatrixStatsAggregation.g.cs
index cb30e9af9a3..92923009786 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Aggregations/MatrixStatsAggregation.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Aggregations/MatrixStatsAggregation.g.cs
@@ -33,6 +33,7 @@ public sealed partial class MatrixStatsAggregation
 	/// <para>An array of fields for computing the statistics.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? Fields { get; set; }
 	[JsonInclude, JsonPropertyName("meta")]
 	public IDictionary<string, object>? Meta { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Aggregations/SignificantTextAggregation.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Aggregations/SignificantTextAggregation.g.cs
index 99c32dc8ccd..4d6ad17d679 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Aggregations/SignificantTextAggregation.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Aggregations/SignificantTextAggregation.g.cs
@@ -133,6 +133,7 @@ public sealed partial class SignificantTextAggregation
 	/// <para>Overrides the JSON `_source` fields from which text will be analyzed.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("source_fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? SourceFields { get; set; }
 
 	public static implicit operator Elastic.Clients.Elasticsearch.Aggregations.Aggregation(SignificantTextAggregation significantTextAggregation) => Elastic.Clients.Elasticsearch.Aggregations.Aggregation.SignificantText(significantTextAggregation);
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Aggregations/TopHitsAggregation.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Aggregations/TopHitsAggregation.g.cs
index 3fce3dd280f..9af6b192925 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Aggregations/TopHitsAggregation.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Aggregations/TopHitsAggregation.g.cs
@@ -33,6 +33,7 @@ public sealed partial class TopHitsAggregation
 	/// <para>Fields for which to return doc values.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("docvalue_fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? DocvalueFields { get; set; }
 
 	/// <summary>
@@ -102,6 +103,7 @@ public sealed partial class TopHitsAggregation
 	/// <para>Returns values for the specified stored fields (fields that use the `store` mapping option).</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("stored_fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? StoredFields { get; set; }
 
 	/// <summary>
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/MGet/MultiGetOperation.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/MGet/MultiGetOperation.g.cs
index 4552a7f8d4c..d5b80a2b1da 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/MGet/MultiGetOperation.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/MGet/MultiGetOperation.g.cs
@@ -57,6 +57,7 @@ public sealed partial class MultiGetOperation
 	/// <para>The stored fields you want to retrieve.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("stored_fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? StoredFields { get; set; }
 	[JsonInclude, JsonPropertyName("version")]
 	public long? Version { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/Mtermvectors/MultiTermVectorsOperation.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/Mtermvectors/MultiTermVectorsOperation.g.cs
index 413f920653b..36f796444d8 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/Mtermvectors/MultiTermVectorsOperation.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/Mtermvectors/MultiTermVectorsOperation.g.cs
@@ -39,6 +39,7 @@ public sealed partial class MultiTermVectorsOperation
 	/// <para>Comma-separated list or wildcard expressions of fields to include in the statistics.<br/>Used as the default list unless a specific field list is provided in the `completion_fields` or `fielddata_fields` parameters.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? Fields { get; set; }
 
 	/// <summary>
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/Reindex/Source.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/Reindex/Source.g.cs
index bc84ae9f20c..cd0e776466b 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/Reindex/Source.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/Reindex/Source.g.cs
@@ -68,6 +68,7 @@ public sealed partial class Source
 	/// <para>If `true` reindexes all source fields.<br/>Set to a list to reindex select fields.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("_source")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? SourceFields { get; set; }
 }
 
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/Search/HighlightField.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/Search/HighlightField.g.cs
index 67eee637d19..e7bdb7cc7c3 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/Search/HighlightField.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/Search/HighlightField.g.cs
@@ -78,6 +78,7 @@ public sealed partial class HighlightField
 	[JsonInclude, JsonPropertyName("highlight_query")]
 	public Elastic.Clients.Elasticsearch.QueryDsl.Query? HighlightQuery { get; set; }
 	[JsonInclude, JsonPropertyName("matched_fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? MatchedFields { get; set; }
 
 	/// <summary>
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/Search/InnerHits.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/Search/InnerHits.g.cs
index 16b1a958d9c..6f798b3d1b4 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/Search/InnerHits.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Core/Search/InnerHits.g.cs
@@ -36,6 +36,7 @@ public sealed partial class InnerHits
 	[JsonInclude, JsonPropertyName("explain")]
 	public bool? Explain { get; set; }
 	[JsonInclude, JsonPropertyName("fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? Fields { get; set; }
 
 	/// <summary>
@@ -73,6 +74,7 @@ public sealed partial class InnerHits
 	[JsonInclude, JsonPropertyName("_source")]
 	public Elastic.Clients.Elasticsearch.Core.Search.SourceConfig? Source { get; set; }
 	[JsonInclude, JsonPropertyName("stored_fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? StoredFields { get; set; }
 	[JsonInclude, JsonPropertyName("track_scores")]
 	public bool? TrackScores { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Enrich/EnrichPolicy.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Enrich/EnrichPolicy.g.cs
index 33f827ae764..fc7a0cf8953 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Enrich/EnrichPolicy.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Enrich/EnrichPolicy.g.cs
@@ -32,6 +32,7 @@ public sealed partial class EnrichPolicy
 	[JsonInclude, JsonPropertyName("elasticsearch_version")]
 	public string? ElasticsearchVersion { get; set; }
 	[JsonInclude, JsonPropertyName("enrich_fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields EnrichFields { get; set; }
 	[JsonInclude, JsonPropertyName("indices")]
 	public Elastic.Clients.Elasticsearch.Indices Indices { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/IndexManagement/IndexSegmentSort.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/IndexManagement/IndexSegmentSort.g.cs
index 97f5d01376a..41e475ffda0 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/IndexManagement/IndexSegmentSort.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/IndexManagement/IndexSegmentSort.g.cs
@@ -30,6 +30,7 @@ namespace Elastic.Clients.Elasticsearch.IndexManagement;
 public sealed partial class IndexSegmentSort
 {
 	[JsonInclude, JsonPropertyName("field")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? Field { get; set; }
 	[JsonInclude, JsonPropertyName("missing")]
 	[SingleOrManyCollectionConverter(typeof(Elastic.Clients.Elasticsearch.IndexManagement.SegmentSortMissing))]
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Ingest/CsvProcessor.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Ingest/CsvProcessor.g.cs
index 1b321131133..6017497a9a9 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Ingest/CsvProcessor.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Ingest/CsvProcessor.g.cs
@@ -93,6 +93,7 @@ public sealed partial class CsvProcessor
 	/// <para>The array of fields to assign extracted values to.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("target_fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields TargetFields { get; set; }
 
 	/// <summary>
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Ingest/RemoveProcessor.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Ingest/RemoveProcessor.g.cs
index a3e15e76be9..a673dca0c16 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Ingest/RemoveProcessor.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Ingest/RemoveProcessor.g.cs
@@ -39,6 +39,7 @@ public sealed partial class RemoveProcessor
 	/// <para>Fields to be removed. Supports template snippets.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("field")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields Field { get; set; }
 
 	/// <summary>
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/MachineLearning/AnalysisConfig.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/MachineLearning/AnalysisConfig.g.cs
index b752d525b17..befb521e2d1 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/MachineLearning/AnalysisConfig.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/MachineLearning/AnalysisConfig.g.cs
@@ -63,7 +63,8 @@ public sealed partial class AnalysisConfig
 	/// <para>A comma separated list of influencer field names. Typically these can be the by, over, or partition fields that are used in the detector configuration. You might also want to use a field name that is not specifically named in a detector, but is available as part of the input data. When you use multiple detectors, the use of influencers is recommended as it aggregates results for each influencer entity.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("influencers")]
-	public ICollection<Elastic.Clients.Elasticsearch.Field>? Influencers { get; set; }
+	[JsonConverter(typeof(FieldsConverter))]
+	public Elastic.Clients.Elasticsearch.Fields? Influencers { get; set; }
 
 	/// <summary>
 	/// <para>The size of the window in which to expect data that is out of time order. If you specify a non-zero value, it must be greater than or equal to one second. NOTE: Latency is applicable only when you send data by using the post data API.</para>
@@ -112,7 +113,7 @@ public AnalysisConfigDescriptor() : base()
 	private Elastic.Clients.Elasticsearch.MachineLearning.DetectorDescriptor<TDocument> DetectorsDescriptor { get; set; }
 	private Action<Elastic.Clients.Elasticsearch.MachineLearning.DetectorDescriptor<TDocument>> DetectorsDescriptorAction { get; set; }
 	private Action<Elastic.Clients.Elasticsearch.MachineLearning.DetectorDescriptor<TDocument>>[] DetectorsDescriptorActions { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Field>? InfluencersValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Fields? InfluencersValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Duration? LatencyValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Duration? ModelPruneWindowValue { get; set; }
 	private bool? MultivariateByFieldsValue { get; set; }
@@ -217,7 +218,7 @@ public AnalysisConfigDescriptor<TDocument> Detectors(params Action<Elastic.Clien
 	/// <summary>
 	/// <para>A comma separated list of influencer field names. Typically these can be the by, over, or partition fields that are used in the detector configuration. You might also want to use a field name that is not specifically named in a detector, but is available as part of the input data. When you use multiple detectors, the use of influencers is recommended as it aggregates results for each influencer entity.</para>
 	/// </summary>
-	public AnalysisConfigDescriptor<TDocument> Influencers(ICollection<Elastic.Clients.Elasticsearch.Field>? influencers)
+	public AnalysisConfigDescriptor<TDocument> Influencers(Elastic.Clients.Elasticsearch.Fields? influencers)
 	{
 		InfluencersValue = influencers;
 		return Self;
@@ -428,7 +429,7 @@ public AnalysisConfigDescriptor() : base()
 	private Elastic.Clients.Elasticsearch.MachineLearning.DetectorDescriptor DetectorsDescriptor { get; set; }
 	private Action<Elastic.Clients.Elasticsearch.MachineLearning.DetectorDescriptor> DetectorsDescriptorAction { get; set; }
 	private Action<Elastic.Clients.Elasticsearch.MachineLearning.DetectorDescriptor>[] DetectorsDescriptorActions { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Field>? InfluencersValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Fields? InfluencersValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Duration? LatencyValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Duration? ModelPruneWindowValue { get; set; }
 	private bool? MultivariateByFieldsValue { get; set; }
@@ -533,7 +534,7 @@ public AnalysisConfigDescriptor Detectors(params Action<Elastic.Clients.Elastics
 	/// <summary>
 	/// <para>A comma separated list of influencer field names. Typically these can be the by, over, or partition fields that are used in the detector configuration. You might also want to use a field name that is not specifically named in a detector, but is available as part of the input data. When you use multiple detectors, the use of influencers is recommended as it aggregates results for each influencer entity.</para>
 	/// </summary>
-	public AnalysisConfigDescriptor Influencers(ICollection<Elastic.Clients.Elasticsearch.Field>? influencers)
+	public AnalysisConfigDescriptor Influencers(Elastic.Clients.Elasticsearch.Fields? influencers)
 	{
 		InfluencersValue = influencers;
 		return Self;
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/BinaryProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/BinaryProperty.g.cs
index 2e2edff572f..a7e917b0c28 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/BinaryProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/BinaryProperty.g.cs
@@ -30,6 +30,7 @@ namespace Elastic.Clients.Elasticsearch.Mapping;
 public sealed partial class BinaryProperty : IProperty
 {
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/BooleanProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/BooleanProperty.g.cs
index 8f51e4e4800..61eacc24813 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/BooleanProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/BooleanProperty.g.cs
@@ -32,6 +32,7 @@ public sealed partial class BooleanProperty : IProperty
 	[JsonInclude, JsonPropertyName("boost")]
 	public double? Boost { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/ByteNumberProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/ByteNumberProperty.g.cs
index ec2c9b75a7f..232c0f9d163 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/ByteNumberProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/ByteNumberProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class ByteNumberProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/CompletionProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/CompletionProperty.g.cs
index 8af9b697ea5..76d33e5ce91 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/CompletionProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/CompletionProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class CompletionProperty : IProperty
 	[JsonInclude, JsonPropertyName("contexts")]
 	public ICollection<Elastic.Clients.Elasticsearch.Mapping.SuggestContext>? Contexts { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DateNanosProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DateNanosProperty.g.cs
index 1e488367faf..1837edc57bc 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DateNanosProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DateNanosProperty.g.cs
@@ -32,6 +32,7 @@ public sealed partial class DateNanosProperty : IProperty
 	[JsonInclude, JsonPropertyName("boost")]
 	public double? Boost { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DateProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DateProperty.g.cs
index ff467cdef77..731360bb852 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DateProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DateProperty.g.cs
@@ -32,6 +32,7 @@ public sealed partial class DateProperty : IProperty
 	[JsonInclude, JsonPropertyName("boost")]
 	public double? Boost { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DateRangeProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DateRangeProperty.g.cs
index 0ec837c0746..fb55e5a8407 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DateRangeProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DateRangeProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class DateRangeProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DoubleNumberProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DoubleNumberProperty.g.cs
index 438c908637d..7ae0120764a 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DoubleNumberProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DoubleNumberProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class DoubleNumberProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DoubleRangeProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DoubleRangeProperty.g.cs
index a69f1a831f9..d6f3d36ffb8 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DoubleRangeProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DoubleRangeProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class DoubleRangeProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DynamicProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DynamicProperty.g.cs
index 2ee5c403f65..96b7efc6fcd 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DynamicProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/DynamicProperty.g.cs
@@ -36,6 +36,7 @@ public sealed partial class DynamicProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/FloatNumberProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/FloatNumberProperty.g.cs
index 56377791f55..29a8c4ad3ef 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/FloatNumberProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/FloatNumberProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class FloatNumberProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/FloatRangeProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/FloatRangeProperty.g.cs
index 8d0226ba413..8c3df0eb6b0 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/FloatRangeProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/FloatRangeProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class FloatRangeProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/GeoPointProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/GeoPointProperty.g.cs
index 709b78ccf20..d1474899865 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/GeoPointProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/GeoPointProperty.g.cs
@@ -30,6 +30,7 @@ namespace Elastic.Clients.Elasticsearch.Mapping;
 public sealed partial class GeoPointProperty : IProperty
 {
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/GeoShapeProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/GeoShapeProperty.g.cs
index 40b74bc573d..054a4784610 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/GeoShapeProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/GeoShapeProperty.g.cs
@@ -36,6 +36,7 @@ public sealed partial class GeoShapeProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/HalfFloatNumberProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/HalfFloatNumberProperty.g.cs
index f90f2ef2541..e37475a1571 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/HalfFloatNumberProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/HalfFloatNumberProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class HalfFloatNumberProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/IntegerNumberProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/IntegerNumberProperty.g.cs
index 74f0b91488d..09df3f6b8f0 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/IntegerNumberProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/IntegerNumberProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class IntegerNumberProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/IntegerRangeProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/IntegerRangeProperty.g.cs
index 3aeb69fba48..2cb1dcddc61 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/IntegerRangeProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/IntegerRangeProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class IntegerRangeProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/IpProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/IpProperty.g.cs
index 0ffd3af867c..8877cba09df 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/IpProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/IpProperty.g.cs
@@ -32,6 +32,7 @@ public sealed partial class IpProperty : IProperty
 	[JsonInclude, JsonPropertyName("boost")]
 	public double? Boost { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/IpRangeProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/IpRangeProperty.g.cs
index 51da78a32fb..4162fa65fe1 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/IpRangeProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/IpRangeProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class IpRangeProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/KeywordProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/KeywordProperty.g.cs
index 7fb1f6c981a..5a85a185b03 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/KeywordProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/KeywordProperty.g.cs
@@ -32,6 +32,7 @@ public sealed partial class KeywordProperty : IProperty
 	[JsonInclude, JsonPropertyName("boost")]
 	public double? Boost { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/LongNumberProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/LongNumberProperty.g.cs
index 937b95e54f2..84e27170b38 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/LongNumberProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/LongNumberProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class LongNumberProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/LongRangeProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/LongRangeProperty.g.cs
index 4992f5cf0c4..e999b768698 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/LongRangeProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/LongRangeProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class LongRangeProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/MatchOnlyTextProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/MatchOnlyTextProperty.g.cs
index a947238545e..aaadecbb80e 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/MatchOnlyTextProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/MatchOnlyTextProperty.g.cs
@@ -36,6 +36,7 @@ public sealed partial class MatchOnlyTextProperty : IProperty
 	/// <para>Allows you to copy the values of multiple fields into a group<br/>field, which can then be queried as a single field.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 
 	/// <summary>
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/Murmur3HashProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/Murmur3HashProperty.g.cs
index ed190e59917..314b5a74efa 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/Murmur3HashProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/Murmur3HashProperty.g.cs
@@ -30,6 +30,7 @@ namespace Elastic.Clients.Elasticsearch.Mapping;
 public sealed partial class Murmur3HashProperty : IProperty
 {
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/NestedProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/NestedProperty.g.cs
index 244294b579e..8157ffa16d7 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/NestedProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/NestedProperty.g.cs
@@ -30,6 +30,7 @@ namespace Elastic.Clients.Elasticsearch.Mapping;
 public sealed partial class NestedProperty : IProperty
 {
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("dynamic")]
 	public Elastic.Clients.Elasticsearch.Mapping.DynamicMapping? Dynamic { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/ObjectProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/ObjectProperty.g.cs
index b28c1b9835d..426174af751 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/ObjectProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/ObjectProperty.g.cs
@@ -30,6 +30,7 @@ namespace Elastic.Clients.Elasticsearch.Mapping;
 public sealed partial class ObjectProperty : IProperty
 {
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("dynamic")]
 	public Elastic.Clients.Elasticsearch.Mapping.DynamicMapping? Dynamic { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/PointProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/PointProperty.g.cs
index acefd42f69a..02c94ce9291 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/PointProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/PointProperty.g.cs
@@ -30,6 +30,7 @@ namespace Elastic.Clients.Elasticsearch.Mapping;
 public sealed partial class PointProperty : IProperty
 {
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/ScaledFloatNumberProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/ScaledFloatNumberProperty.g.cs
index 0bf03b234bf..93ca150ebde 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/ScaledFloatNumberProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/ScaledFloatNumberProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class ScaledFloatNumberProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/SearchAsYouTypeProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/SearchAsYouTypeProperty.g.cs
index ce9c71e6272..99ee3774a20 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/SearchAsYouTypeProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/SearchAsYouTypeProperty.g.cs
@@ -32,6 +32,7 @@ public sealed partial class SearchAsYouTypeProperty : IProperty
 	[JsonInclude, JsonPropertyName("analyzer")]
 	public string? Analyzer { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("dynamic")]
 	public Elastic.Clients.Elasticsearch.Mapping.DynamicMapping? Dynamic { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/ShapeProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/ShapeProperty.g.cs
index 771b77ef556..357f6463ed0 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/ShapeProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/ShapeProperty.g.cs
@@ -36,6 +36,7 @@ public sealed partial class ShapeProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/ShortNumberProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/ShortNumberProperty.g.cs
index 857658c3521..07d7d45b7aa 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/ShortNumberProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/ShortNumberProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class ShortNumberProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/TextProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/TextProperty.g.cs
index 6fd45a2d632..361df3fb774 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/TextProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/TextProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class TextProperty : IProperty
 	[JsonInclude, JsonPropertyName("boost")]
 	public double? Boost { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("dynamic")]
 	public Elastic.Clients.Elasticsearch.Mapping.DynamicMapping? Dynamic { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/TokenCountProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/TokenCountProperty.g.cs
index b99e9ac7262..0d2b18067bd 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/TokenCountProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/TokenCountProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class TokenCountProperty : IProperty
 	[JsonInclude, JsonPropertyName("boost")]
 	public double? Boost { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/UnsignedLongNumberProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/UnsignedLongNumberProperty.g.cs
index 290d235b46a..b590ebdb37a 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/UnsignedLongNumberProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/UnsignedLongNumberProperty.g.cs
@@ -34,6 +34,7 @@ public sealed partial class UnsignedLongNumberProperty : IProperty
 	[JsonInclude, JsonPropertyName("coerce")]
 	public bool? Coerce { get; set; }
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/VersionProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/VersionProperty.g.cs
index b04d5bb927f..a8f66f2a807 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/VersionProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/VersionProperty.g.cs
@@ -30,6 +30,7 @@ namespace Elastic.Clients.Elasticsearch.Mapping;
 public sealed partial class VersionProperty : IProperty
 {
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/WildcardProperty.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/WildcardProperty.g.cs
index 5f71a6ea621..e4bff5cfb5a 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/WildcardProperty.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Mapping/WildcardProperty.g.cs
@@ -30,6 +30,7 @@ namespace Elastic.Clients.Elasticsearch.Mapping;
 public sealed partial class WildcardProperty : IProperty
 {
 	[JsonInclude, JsonPropertyName("copy_to")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? CopyTo { get; set; }
 	[JsonInclude, JsonPropertyName("doc_values")]
 	public bool? DocValues { get; set; }
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/CombinedFieldsQuery.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/CombinedFieldsQuery.g.cs
index cc34a6da6a4..600e97989e3 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/CombinedFieldsQuery.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/CombinedFieldsQuery.g.cs
@@ -45,7 +45,8 @@ public sealed partial class CombinedFieldsQuery
 	/// <para>List of fields to search. Field wildcard patterns are allowed. Only `text` fields are supported, and they must all have the same search `analyzer`.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("fields")]
-	public ICollection<Elastic.Clients.Elasticsearch.Field> Fields { get; set; }
+	[JsonConverter(typeof(FieldsConverter))]
+	public Elastic.Clients.Elasticsearch.Fields Fields { get; set; }
 
 	/// <summary>
 	/// <para>Minimum number of clauses that must match for a document to be returned.</para>
@@ -86,7 +87,7 @@ public CombinedFieldsQueryDescriptor() : base()
 
 	private bool? AutoGenerateSynonymsPhraseQueryValue { get; set; }
 	private float? BoostValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Field> FieldsValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Fields FieldsValue { get; set; }
 	private Elastic.Clients.Elasticsearch.MinimumShouldMatch? MinimumShouldMatchValue { get; set; }
 	private Elastic.Clients.Elasticsearch.QueryDsl.CombinedFieldsOperator? OperatorValue { get; set; }
 	private string QueryValue { get; set; }
@@ -114,7 +115,7 @@ public CombinedFieldsQueryDescriptor<TDocument> Boost(float? boost)
 	/// <summary>
 	/// <para>List of fields to search. Field wildcard patterns are allowed. Only `text` fields are supported, and they must all have the same search `analyzer`.</para>
 	/// </summary>
-	public CombinedFieldsQueryDescriptor<TDocument> Fields(ICollection<Elastic.Clients.Elasticsearch.Field> fields)
+	public CombinedFieldsQueryDescriptor<TDocument> Fields(Elastic.Clients.Elasticsearch.Fields fields)
 	{
 		FieldsValue = fields;
 		return Self;
@@ -219,7 +220,7 @@ public CombinedFieldsQueryDescriptor() : base()
 
 	private bool? AutoGenerateSynonymsPhraseQueryValue { get; set; }
 	private float? BoostValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Field> FieldsValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Fields FieldsValue { get; set; }
 	private Elastic.Clients.Elasticsearch.MinimumShouldMatch? MinimumShouldMatchValue { get; set; }
 	private Elastic.Clients.Elasticsearch.QueryDsl.CombinedFieldsOperator? OperatorValue { get; set; }
 	private string QueryValue { get; set; }
@@ -247,7 +248,7 @@ public CombinedFieldsQueryDescriptor Boost(float? boost)
 	/// <summary>
 	/// <para>List of fields to search. Field wildcard patterns are allowed. Only `text` fields are supported, and they must all have the same search `analyzer`.</para>
 	/// </summary>
-	public CombinedFieldsQueryDescriptor Fields(ICollection<Elastic.Clients.Elasticsearch.Field> fields)
+	public CombinedFieldsQueryDescriptor Fields(Elastic.Clients.Elasticsearch.Fields fields)
 	{
 		FieldsValue = fields;
 		return Self;
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/LikeDocument.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/LikeDocument.g.cs
index 1e951a1636c..65c3dd7969b 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/LikeDocument.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/LikeDocument.g.cs
@@ -35,7 +35,8 @@ public sealed partial class LikeDocument
 	[JsonInclude, JsonPropertyName("doc")]
 	public object? Doc { get; set; }
 	[JsonInclude, JsonPropertyName("fields")]
-	public ICollection<Elastic.Clients.Elasticsearch.Field>? Fields { get; set; }
+	[JsonConverter(typeof(FieldsConverter))]
+	public Elastic.Clients.Elasticsearch.Fields? Fields { get; set; }
 
 	/// <summary>
 	/// <para>ID of a document.</para>
@@ -67,7 +68,7 @@ public LikeDocumentDescriptor() : base()
 	}
 
 	private object? DocValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Field>? FieldsValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Fields? FieldsValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Id? IdValue { get; set; }
 	private Elastic.Clients.Elasticsearch.IndexName? IndexValue { get; set; }
 	private IDictionary<Elastic.Clients.Elasticsearch.Field, string>? PerFieldAnalyzerValue { get; set; }
@@ -84,7 +85,7 @@ public LikeDocumentDescriptor<TDocument> Doc(object? doc)
 		return Self;
 	}
 
-	public LikeDocumentDescriptor<TDocument> Fields(ICollection<Elastic.Clients.Elasticsearch.Field>? fields)
+	public LikeDocumentDescriptor<TDocument> Fields(Elastic.Clients.Elasticsearch.Fields? fields)
 	{
 		FieldsValue = fields;
 		return Self;
@@ -196,7 +197,7 @@ public LikeDocumentDescriptor() : base()
 	}
 
 	private object? DocValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Field>? FieldsValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Fields? FieldsValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Id? IdValue { get; set; }
 	private Elastic.Clients.Elasticsearch.IndexName? IndexValue { get; set; }
 	private IDictionary<Elastic.Clients.Elasticsearch.Field, string>? PerFieldAnalyzerValue { get; set; }
@@ -213,7 +214,7 @@ public LikeDocumentDescriptor Doc(object? doc)
 		return Self;
 	}
 
-	public LikeDocumentDescriptor Fields(ICollection<Elastic.Clients.Elasticsearch.Field>? fields)
+	public LikeDocumentDescriptor Fields(Elastic.Clients.Elasticsearch.Fields? fields)
 	{
 		FieldsValue = fields;
 		return Self;
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/MoreLikeThisQuery.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/MoreLikeThisQuery.g.cs
index 5fba455f0e6..af18b10b190 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/MoreLikeThisQuery.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/MoreLikeThisQuery.g.cs
@@ -57,7 +57,8 @@ public sealed partial class MoreLikeThisQuery
 	/// <para>A list of fields to fetch and analyze the text from.<br/>Defaults to the `index.query.default_field` index setting, which has a default value of `*`.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("fields")]
-	public ICollection<Elastic.Clients.Elasticsearch.Field>? Fields { get; set; }
+	[JsonConverter(typeof(FieldsConverter))]
+	public Elastic.Clients.Elasticsearch.Fields? Fields { get; set; }
 
 	/// <summary>
 	/// <para>Specifies whether the input documents should also be included in the search results returned.</para>
@@ -157,7 +158,7 @@ public MoreLikeThisQueryDescriptor() : base()
 	private float? BoostValue { get; set; }
 	private double? BoostTermsValue { get; set; }
 	private bool? FailOnUnsupportedFieldValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Field>? FieldsValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Fields? FieldsValue { get; set; }
 	private bool? IncludeValue { get; set; }
 	private ICollection<Elastic.Clients.Elasticsearch.QueryDsl.Like> LikeValue { get; set; }
 	private int? MaxDocFreqValue { get; set; }
@@ -214,7 +215,7 @@ public MoreLikeThisQueryDescriptor<TDocument> FailOnUnsupportedField(bool? failO
 	/// <summary>
 	/// <para>A list of fields to fetch and analyze the text from.<br/>Defaults to the `index.query.default_field` index setting, which has a default value of `*`.</para>
 	/// </summary>
-	public MoreLikeThisQueryDescriptor<TDocument> Fields(ICollection<Elastic.Clients.Elasticsearch.Field>? fields)
+	public MoreLikeThisQueryDescriptor<TDocument> Fields(Elastic.Clients.Elasticsearch.Fields? fields)
 	{
 		FieldsValue = fields;
 		return Self;
@@ -493,7 +494,7 @@ public MoreLikeThisQueryDescriptor() : base()
 	private float? BoostValue { get; set; }
 	private double? BoostTermsValue { get; set; }
 	private bool? FailOnUnsupportedFieldValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Field>? FieldsValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Fields? FieldsValue { get; set; }
 	private bool? IncludeValue { get; set; }
 	private ICollection<Elastic.Clients.Elasticsearch.QueryDsl.Like> LikeValue { get; set; }
 	private int? MaxDocFreqValue { get; set; }
@@ -550,7 +551,7 @@ public MoreLikeThisQueryDescriptor FailOnUnsupportedField(bool? failOnUnsupporte
 	/// <summary>
 	/// <para>A list of fields to fetch and analyze the text from.<br/>Defaults to the `index.query.default_field` index setting, which has a default value of `*`.</para>
 	/// </summary>
-	public MoreLikeThisQueryDescriptor Fields(ICollection<Elastic.Clients.Elasticsearch.Field>? fields)
+	public MoreLikeThisQueryDescriptor Fields(Elastic.Clients.Elasticsearch.Fields? fields)
 	{
 		FieldsValue = fields;
 		return Self;
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/MultiMatchQuery.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/MultiMatchQuery.g.cs
index 6fb6c7fb0ab..d16ab8d4aac 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/MultiMatchQuery.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/MultiMatchQuery.g.cs
@@ -51,6 +51,7 @@ public sealed partial class MultiMatchQuery
 	/// <para>The fields to be queried.<br/>Defaults to the `index.query.default_field` index settings, which in turn defaults to `*`.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields? Fields { get; set; }
 
 	/// <summary>
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/QueryStringQuery.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/QueryStringQuery.g.cs
index 12efb5414ce..680ad490729 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/QueryStringQuery.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/QueryStringQuery.g.cs
@@ -83,7 +83,8 @@ public sealed partial class QueryStringQuery
 	/// <para>Array of fields to search. Supports wildcards (`*`).</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("fields")]
-	public ICollection<Elastic.Clients.Elasticsearch.Field>? Fields { get; set; }
+	[JsonConverter(typeof(FieldsConverter))]
+	public Elastic.Clients.Elasticsearch.Fields? Fields { get; set; }
 
 	/// <summary>
 	/// <para>Maximum edit distance allowed for fuzzy matching.</para>
@@ -203,7 +204,7 @@ public QueryStringQueryDescriptor() : base()
 	private Elastic.Clients.Elasticsearch.QueryDsl.Operator? DefaultOperatorValue { get; set; }
 	private bool? EnablePositionIncrementsValue { get; set; }
 	private bool? EscapeValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Field>? FieldsValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Fields? FieldsValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Fuzziness? FuzzinessValue { get; set; }
 	private int? FuzzyMaxExpansionsValue { get; set; }
 	private int? FuzzyPrefixLengthValue { get; set; }
@@ -321,7 +322,7 @@ public QueryStringQueryDescriptor<TDocument> Escape(bool? escape = true)
 	/// <summary>
 	/// <para>Array of fields to search. Supports wildcards (`*`).</para>
 	/// </summary>
-	public QueryStringQueryDescriptor<TDocument> Fields(ICollection<Elastic.Clients.Elasticsearch.Field>? fields)
+	public QueryStringQueryDescriptor<TDocument> Fields(Elastic.Clients.Elasticsearch.Fields? fields)
 	{
 		FieldsValue = fields;
 		return Self;
@@ -659,7 +660,7 @@ public QueryStringQueryDescriptor() : base()
 	private Elastic.Clients.Elasticsearch.QueryDsl.Operator? DefaultOperatorValue { get; set; }
 	private bool? EnablePositionIncrementsValue { get; set; }
 	private bool? EscapeValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Field>? FieldsValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Fields? FieldsValue { get; set; }
 	private Elastic.Clients.Elasticsearch.Fuzziness? FuzzinessValue { get; set; }
 	private int? FuzzyMaxExpansionsValue { get; set; }
 	private int? FuzzyPrefixLengthValue { get; set; }
@@ -777,7 +778,7 @@ public QueryStringQueryDescriptor Escape(bool? escape = true)
 	/// <summary>
 	/// <para>Array of fields to search. Supports wildcards (`*`).</para>
 	/// </summary>
-	public QueryStringQueryDescriptor Fields(ICollection<Elastic.Clients.Elasticsearch.Field>? fields)
+	public QueryStringQueryDescriptor Fields(Elastic.Clients.Elasticsearch.Fields? fields)
 	{
 		FieldsValue = fields;
 		return Self;
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/SimpleQueryStringQuery.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/SimpleQueryStringQuery.g.cs
index bde33a29ec9..9a3ebf84ee1 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/SimpleQueryStringQuery.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/QueryDsl/SimpleQueryStringQuery.g.cs
@@ -63,7 +63,8 @@ public sealed partial class SimpleQueryStringQuery
 	/// <para>Array of fields you wish to search.<br/>Accepts wildcard expressions.<br/>You also can boost relevance scores for matches to particular fields using a caret (`^`) notation.<br/>Defaults to the `index.query.default_field index` setting, which has a default value of `*`.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("fields")]
-	public ICollection<Elastic.Clients.Elasticsearch.Field>? Fields { get; set; }
+	[JsonConverter(typeof(FieldsConverter))]
+	public Elastic.Clients.Elasticsearch.Fields? Fields { get; set; }
 
 	/// <summary>
 	/// <para>List of enabled operators for the simple query string syntax.</para>
@@ -131,7 +132,7 @@ public SimpleQueryStringQueryDescriptor() : base()
 	private bool? AutoGenerateSynonymsPhraseQueryValue { get; set; }
 	private float? BoostValue { get; set; }
 	private Elastic.Clients.Elasticsearch.QueryDsl.Operator? DefaultOperatorValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Field>? FieldsValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Fields? FieldsValue { get; set; }
 	private Elastic.Clients.Elasticsearch.QueryDsl.SimpleQueryStringFlag? FlagsValue { get; set; }
 	private int? FuzzyMaxExpansionsValue { get; set; }
 	private int? FuzzyPrefixLengthValue { get; set; }
@@ -190,7 +191,7 @@ public SimpleQueryStringQueryDescriptor<TDocument> DefaultOperator(Elastic.Clien
 	/// <summary>
 	/// <para>Array of fields you wish to search.<br/>Accepts wildcard expressions.<br/>You also can boost relevance scores for matches to particular fields using a caret (`^`) notation.<br/>Defaults to the `index.query.default_field index` setting, which has a default value of `*`.</para>
 	/// </summary>
-	public SimpleQueryStringQueryDescriptor<TDocument> Fields(ICollection<Elastic.Clients.Elasticsearch.Field>? fields)
+	public SimpleQueryStringQueryDescriptor<TDocument> Fields(Elastic.Clients.Elasticsearch.Fields? fields)
 	{
 		FieldsValue = fields;
 		return Self;
@@ -380,7 +381,7 @@ public SimpleQueryStringQueryDescriptor() : base()
 	private bool? AutoGenerateSynonymsPhraseQueryValue { get; set; }
 	private float? BoostValue { get; set; }
 	private Elastic.Clients.Elasticsearch.QueryDsl.Operator? DefaultOperatorValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Field>? FieldsValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Fields? FieldsValue { get; set; }
 	private Elastic.Clients.Elasticsearch.QueryDsl.SimpleQueryStringFlag? FlagsValue { get; set; }
 	private int? FuzzyMaxExpansionsValue { get; set; }
 	private int? FuzzyPrefixLengthValue { get; set; }
@@ -439,7 +440,7 @@ public SimpleQueryStringQueryDescriptor DefaultOperator(Elastic.Clients.Elastics
 	/// <summary>
 	/// <para>Array of fields you wish to search.<br/>Accepts wildcard expressions.<br/>You also can boost relevance scores for matches to particular fields using a caret (`^`) notation.<br/>Defaults to the `index.query.default_field index` setting, which has a default value of `*`.</para>
 	/// </summary>
-	public SimpleQueryStringQueryDescriptor Fields(ICollection<Elastic.Clients.Elasticsearch.Field>? fields)
+	public SimpleQueryStringQueryDescriptor Fields(Elastic.Clients.Elasticsearch.Fields? fields)
 	{
 		FieldsValue = fields;
 		return Self;
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Rollup/HistogramGrouping.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Rollup/HistogramGrouping.g.cs
index 0fdea00013e..e84b8e738a1 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Rollup/HistogramGrouping.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Rollup/HistogramGrouping.g.cs
@@ -33,6 +33,7 @@ public sealed partial class HistogramGrouping
 	/// <para>The set of fields that you wish to build histograms for.<br/>All fields specified must be some kind of numeric.<br/>Order does not matter.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields Fields { get; set; }
 
 	/// <summary>
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Rollup/TermsGrouping.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Rollup/TermsGrouping.g.cs
index 34df9eaac4a..66264bbb8ba 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/Rollup/TermsGrouping.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/Rollup/TermsGrouping.g.cs
@@ -33,6 +33,7 @@ public sealed partial class TermsGrouping
 	/// <para>The set of fields that you wish to collect terms for.<br/>This array can contain fields that are both keyword and numerics.<br/>Order does not matter.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("fields")]
+	[JsonConverter(typeof(SingleOrManyFieldsConverter))]
 	public Elastic.Clients.Elasticsearch.Fields Fields { get; set; }
 }
 
diff --git a/src/Elastic.Clients.Elasticsearch/_Generated/Types/TransformManagement/Latest.g.cs b/src/Elastic.Clients.Elasticsearch/_Generated/Types/TransformManagement/Latest.g.cs
index c34b83e86c0..ff72c818747 100644
--- a/src/Elastic.Clients.Elasticsearch/_Generated/Types/TransformManagement/Latest.g.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Generated/Types/TransformManagement/Latest.g.cs
@@ -39,7 +39,8 @@ public sealed partial class Latest
 	/// <para>Specifies an array of one or more fields that are used to group the data.</para>
 	/// </summary>
 	[JsonInclude, JsonPropertyName("unique_key")]
-	public ICollection<Elastic.Clients.Elasticsearch.Field> UniqueKey { get; set; }
+	[JsonConverter(typeof(FieldsConverter))]
+	public Elastic.Clients.Elasticsearch.Fields UniqueKey { get; set; }
 }
 
 public sealed partial class LatestDescriptor<TDocument> : SerializableDescriptor<LatestDescriptor<TDocument>>
@@ -51,7 +52,7 @@ public LatestDescriptor() : base()
 	}
 
 	private Elastic.Clients.Elasticsearch.Field SortValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Field> UniqueKeyValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Fields UniqueKeyValue { get; set; }
 
 	/// <summary>
 	/// <para>Specifies the date field that is used to identify the latest documents.</para>
@@ -83,7 +84,7 @@ public LatestDescriptor<TDocument> Sort(Expression<Func<TDocument, object>> sort
 	/// <summary>
 	/// <para>Specifies an array of one or more fields that are used to group the data.</para>
 	/// </summary>
-	public LatestDescriptor<TDocument> UniqueKey(ICollection<Elastic.Clients.Elasticsearch.Field> uniqueKey)
+	public LatestDescriptor<TDocument> UniqueKey(Elastic.Clients.Elasticsearch.Fields uniqueKey)
 	{
 		UniqueKeyValue = uniqueKey;
 		return Self;
@@ -109,7 +110,7 @@ public LatestDescriptor() : base()
 	}
 
 	private Elastic.Clients.Elasticsearch.Field SortValue { get; set; }
-	private ICollection<Elastic.Clients.Elasticsearch.Field> UniqueKeyValue { get; set; }
+	private Elastic.Clients.Elasticsearch.Fields UniqueKeyValue { get; set; }
 
 	/// <summary>
 	/// <para>Specifies the date field that is used to identify the latest documents.</para>
@@ -141,7 +142,7 @@ public LatestDescriptor Sort<TDocument>(Expression<Func<TDocument, object>> sort
 	/// <summary>
 	/// <para>Specifies an array of one or more fields that are used to group the data.</para>
 	/// </summary>
-	public LatestDescriptor UniqueKey(ICollection<Elastic.Clients.Elasticsearch.Field> uniqueKey)
+	public LatestDescriptor UniqueKey(Elastic.Clients.Elasticsearch.Fields uniqueKey)
 	{
 		UniqueKeyValue = uniqueKey;
 		return Self;