From 56137f7431e09f7485fcdffb21681bac56b7d4d5 Mon Sep 17 00:00:00 2001
From: Thomas Li <47963215+lithomas1@users.noreply.github.com>
Date: Thu, 21 Sep 2023 21:19:03 -0400
Subject: [PATCH 1/3] DEPR: Change FutureWarning for observed=False to
 DeprecationWarning

---
 doc/source/whatsnew/v2.1.1.rst           | 1 +
 pandas/core/groupby/groupby.py           | 2 +-
 pandas/tests/groupby/test_categorical.py | 2 +-
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/doc/source/whatsnew/v2.1.1.rst b/doc/source/whatsnew/v2.1.1.rst
index c52f7db8ec3ec..0f3ee6cf582d9 100644
--- a/doc/source/whatsnew/v2.1.1.rst
+++ b/doc/source/whatsnew/v2.1.1.rst
@@ -44,6 +44,7 @@ Bug fixes
 
 Other
 ~~~~~
+- Changed the ``FutureWarning`` raised when ``observed=False`` in :meth:`DataFrame.groupby` and :meth:`Series.groupby` to a ``DeprecationWarning`` (:issue:`54970`)
 - Reverted the deprecation that disallowed :meth:`Series.apply` returning a :class:`DataFrame` when the passed-in callable returns a :class:`Series` object (:issue:`52116`)
 
 .. ---------------------------------------------------------------------------
diff --git a/pandas/core/groupby/groupby.py b/pandas/core/groupby/groupby.py
index d607baf18d6cb..942358b6db3de 100644
--- a/pandas/core/groupby/groupby.py
+++ b/pandas/core/groupby/groupby.py
@@ -1322,7 +1322,7 @@ def __init__(
                     "to True in a future version of pandas. Pass observed=False to "
                     "retain current behavior or observed=True to adopt the future "
                     "default and silence this warning.",
-                    FutureWarning,
+                    DeprecationWarning,
                     stacklevel=find_stack_level(),
                 )
             observed = False
diff --git a/pandas/tests/groupby/test_categorical.py b/pandas/tests/groupby/test_categorical.py
index b11240c841420..cb083eed4c2fc 100644
--- a/pandas/tests/groupby/test_categorical.py
+++ b/pandas/tests/groupby/test_categorical.py
@@ -2080,7 +2080,7 @@ def test_groupby_default_depr(cat_columns, keys):
     df = DataFrame({"a": [1, 1, 2, 3], "b": [4, 5, 6, 7]})
     df[cat_columns] = df[cat_columns].astype("category")
     msg = "The default of observed=False is deprecated"
-    klass = FutureWarning if set(cat_columns) & set(keys) else None
+    klass = DeprecationWarning if set(cat_columns) & set(keys) else None
     with tm.assert_produces_warning(klass, match=msg):
         df.groupby(keys)
 

From 9d7f4a1863bd369e7182d48318f81ebdd32ccb3c Mon Sep 17 00:00:00 2001
From: Thomas Li <47963215+lithomas1@users.noreply.github.com>
Date: Thu, 21 Sep 2023 21:22:51 -0400
Subject: [PATCH 2/3] move note

---
 doc/source/whatsnew/v2.1.1.rst | 1 -
 doc/source/whatsnew/v2.1.2.rst | 2 +-
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/doc/source/whatsnew/v2.1.1.rst b/doc/source/whatsnew/v2.1.1.rst
index 0f3ee6cf582d9..fd19277c36867 100644
--- a/doc/source/whatsnew/v2.1.1.rst
+++ b/doc/source/whatsnew/v2.1.1.rst
@@ -45,7 +45,6 @@ Bug fixes
 Other
 ~~~~~
 - Changed the ``FutureWarning`` raised when ``observed=False`` in :meth:`DataFrame.groupby` and :meth:`Series.groupby` to a ``DeprecationWarning`` (:issue:`54970`)
-- Reverted the deprecation that disallowed :meth:`Series.apply` returning a :class:`DataFrame` when the passed-in callable returns a :class:`Series` object (:issue:`52116`)
 
 .. ---------------------------------------------------------------------------
 .. _whatsnew_211.contributors:
diff --git a/doc/source/whatsnew/v2.1.2.rst b/doc/source/whatsnew/v2.1.2.rst
index 2c9b10160d144..c44374171f16d 100644
--- a/doc/source/whatsnew/v2.1.2.rst
+++ b/doc/source/whatsnew/v2.1.2.rst
@@ -29,7 +29,7 @@ Bug fixes
 
 Other
 ~~~~~
--
+- Reverted the deprecation that disallowed :meth:`Series.apply` returning a :class:`DataFrame` when the passed-in callable returns a :class:`Series` object (:issue:`52116`)
 -
 
 .. ---------------------------------------------------------------------------

From a8b9ac74bd755b1966a9e701c59c243f77a3c94c Mon Sep 17 00:00:00 2001
From: Thomas Li <47963215+lithomas1@users.noreply.github.com>
Date: Thu, 21 Sep 2023 21:25:28 -0400
Subject: [PATCH 3/3] swap order

---
 doc/source/whatsnew/v2.1.1.rst | 2 +-
 doc/source/whatsnew/v2.1.2.rst | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/doc/source/whatsnew/v2.1.1.rst b/doc/source/whatsnew/v2.1.1.rst
index fd19277c36867..c52f7db8ec3ec 100644
--- a/doc/source/whatsnew/v2.1.1.rst
+++ b/doc/source/whatsnew/v2.1.1.rst
@@ -44,7 +44,7 @@ Bug fixes
 
 Other
 ~~~~~
-- Changed the ``FutureWarning`` raised when ``observed=False`` in :meth:`DataFrame.groupby` and :meth:`Series.groupby` to a ``DeprecationWarning`` (:issue:`54970`)
+- Reverted the deprecation that disallowed :meth:`Series.apply` returning a :class:`DataFrame` when the passed-in callable returns a :class:`Series` object (:issue:`52116`)
 
 .. ---------------------------------------------------------------------------
 .. _whatsnew_211.contributors:
diff --git a/doc/source/whatsnew/v2.1.2.rst b/doc/source/whatsnew/v2.1.2.rst
index c44374171f16d..bbf7368513fd4 100644
--- a/doc/source/whatsnew/v2.1.2.rst
+++ b/doc/source/whatsnew/v2.1.2.rst
@@ -29,7 +29,7 @@ Bug fixes
 
 Other
 ~~~~~
-- Reverted the deprecation that disallowed :meth:`Series.apply` returning a :class:`DataFrame` when the passed-in callable returns a :class:`Series` object (:issue:`52116`)
+- Changed the ``FutureWarning`` raised when ``observed=False`` in :meth:`DataFrame.groupby` and :meth:`Series.groupby` to a ``DeprecationWarning`` (:issue:`54970`)
 -
 
 .. ---------------------------------------------------------------------------