diff --git a/awslambdaric/lambda_runtime_marshaller.py b/awslambdaric/lambda_runtime_marshaller.py
index 42ee127..3b28313 100644
--- a/awslambdaric/lambda_runtime_marshaller.py
+++ b/awslambdaric/lambda_runtime_marshaller.py
@@ -16,9 +16,9 @@
 class Encoder(json.JSONEncoder):
     def __init__(self):
         if os.environ.get("AWS_EXECUTION_ENV") == "AWS_Lambda_python3.12":
-            super().__init__(use_decimal=False, ensure_ascii=False)
+            super().__init__(use_decimal=False, ensure_ascii=False, allow_nan=True)
         else:
-            super().__init__(use_decimal=False)
+            super().__init__(use_decimal=False, allow_nan=True)
 
     def default(self, obj):
         if isinstance(obj, decimal.Decimal):
diff --git a/requirements/base.txt b/requirements/base.txt
index 135561f..819c723 100644
--- a/requirements/base.txt
+++ b/requirements/base.txt
@@ -1 +1 @@
-simplejson==3.18.4
+simplejson>=3.18.4