diff --git a/CHANGELOG.mdx b/CHANGELOG.mdx
index a97640d0772b..d1290c72e19e 100644
--- a/CHANGELOG.mdx
+++ b/CHANGELOG.mdx
@@ -16,6 +16,31 @@ https://github.com/RasaHQ/rasa/tree/main/changelog/ . -->
 
 <!-- TOWNCRIER -->
 
+## [3.6.21] - 2025-01-13
+                        
+Rasa 3.6.21 (2025-01-13)                         
+### Bugfixes
+- [#1424](https://github.com/rasahq/rasa/issues/1424): Replace `pickle` and `joblib` with safer alternatives, e.g. `json`, `safetensors`, and `skops`, for
+  serializing components.
+
+  **Note**: This is a model breaking change. Please retrain your model.
+
+  If you have a custom component that inherits from one of the components listed below and modified the `persist` or
+  `load` method, make sure to update your code. Please contact us in case you encounter any problems.
+
+  Affected components:
+
+  - `CountVectorFeaturizer`
+  - `LexicalSyntacticFeaturizer`
+  - `LogisticRegressionClassifier`
+  - `SklearnIntentClassifier`
+  - `DIETClassifier`
+  - `CRFEntityExtractor`
+  - `TrackerFeaturizer`
+  - `TEDPolicy`
+  - `UnexpectedIntentTEDPolicy`
+
+
 ## [3.6.20] - 2024-04-18
                         
 Rasa 3.6.20 (2024-04-18)                         
diff --git a/changelog/1424.bugfix.md b/changelog/1424.bugfix.md
deleted file mode 100644
index d71648f6da3c..000000000000
--- a/changelog/1424.bugfix.md
+++ /dev/null
@@ -1,19 +0,0 @@
-Replace `pickle` and `joblib` with safer alternatives, e.g. `json`, `safetensors`, and `skops`, for
-serializing components.
-
-**Note**: This is a model breaking change. Please retrain your model.
-
-If you have a custom component that inherits from one of the components listed below and modified the `persist` or
-`load` method, make sure to update your code. Please contact us in case you encounter any problems.
-
-Affected components:
-
-- `CountVectorFeaturizer`
-- `LexicalSyntacticFeaturizer`
-- `LogisticRegressionClassifier`
-- `SklearnIntentClassifier`
-- `DIETClassifier`
-- `CRFEntityExtractor`
-- `TrackerFeaturizer`
-- `TEDPolicy`
-- `UnexpectedIntentTEDPolicy`
\ No newline at end of file
diff --git a/pyproject.toml b/pyproject.toml
index d2a48c527aab..c37977e46891 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -9,7 +9,7 @@ exclude = "((.eggs | .git | .pytest_cache | build | dist))"
 
 [tool.poetry]
 name = "rasa"
-version = "3.6.20"
+version = "3.6.21"
 description = "Open source machine learning framework to automate text- and voice-based conversations: NLU, dialogue management, connect to Slack, Facebook, and more - Create chatbots and voice assistants"
 authors = [ "Rasa Technologies GmbH <hi@rasa.com>",]
 maintainers = [ "Tom Bocklisch <tom@rasa.com>",]
@@ -156,7 +156,6 @@ certifi = ">=2023.7.22"
 cryptography = ">=41.0.7"
 skops = "0.9.0"
 safetensors = "~0.4.5"
-
 [[tool.poetry.dependencies.tensorflow-io-gcs-filesystem]]
 version = "==0.31"
 markers = "sys_platform == 'win32'"
diff --git a/rasa/constants.py b/rasa/constants.py
index ef973613bc96..ba883c66b0e0 100644
--- a/rasa/constants.py
+++ b/rasa/constants.py
@@ -18,7 +18,7 @@
 CONFIG_TELEMETRY_ENABLED = "enabled"
 CONFIG_TELEMETRY_DATE = "date"
 
-MINIMUM_COMPATIBLE_VERSION = "3.5.0"
+MINIMUM_COMPATIBLE_VERSION = "3.6.21"
 
 GLOBAL_USER_CONFIG_PATH = os.path.expanduser("~/.config/rasa/global.yml")
 
diff --git a/rasa/version.py b/rasa/version.py
index 2e1490a6a8c3..3b9621033a5d 100644
--- a/rasa/version.py
+++ b/rasa/version.py
@@ -1,3 +1,3 @@
 # this file will automatically be changed,
 # do not add anything but the version number here!
-__version__ = "3.6.20"
+__version__ = "3.6.21"
diff --git a/tests/engine/storage/test_local_model_storage.py b/tests/engine/storage/test_local_model_storage.py
index 9324c399c948..789aa0638568 100644
--- a/tests/engine/storage/test_local_model_storage.py
+++ b/tests/engine/storage/test_local_model_storage.py
@@ -2,21 +2,21 @@
 import uuid
 from datetime import datetime
 from pathlib import Path
-from tarsafe import TarSafe
 
 import freezegun
 import pytest
 from _pytest.monkeypatch import MonkeyPatch
 from _pytest.tmpdir import TempPathFactory
+from tarsafe import TarSafe
 
 import rasa.shared.utils.io
-from rasa.engine.graph import SchemaNode, GraphSchema, GraphModelConfiguration
+from rasa.engine.graph import GraphModelConfiguration, GraphSchema, SchemaNode
 from rasa.engine.storage.local_model_storage import (
-    LocalModelStorage,
     MODEL_ARCHIVE_METADATA_FILE,
+    LocalModelStorage,
 )
-from rasa.engine.storage.storage import ModelStorage, ModelMetadata
 from rasa.engine.storage.resource import Resource
+from rasa.engine.storage.storage import ModelMetadata, ModelStorage
 from rasa.exceptions import UnsupportedModelVersionError
 from rasa.shared.core.domain import Domain
 from rasa.shared.data import TrainingType
@@ -96,7 +96,7 @@ def test_read_long_resource_names_windows(
     domain: Domain,
 ):
     model_dir = tmp_path_factory.mktemp("model_dir")
-    version = "3.5.0"
+    version = "3.6.21"
 
     # full path length > 260 chars
     # but each component of the path needs to be below 255 chars