diff --git a/CHANGES.md b/CHANGES.md
index 206859cff7eee97d917cd2e6d91ac4d12128df63..a41abbefbaf79983533ba2a1b84a3459f1d9db0e 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,12 @@
+Synapse 1.33.1 (2021-05-06)
+===========================
+
+Bugfixes
+--------
+
+- Fix bug where `/sync` would break if using the latest version of `attrs` dependency, by pinning to a previous version. ([\#9937](https://github.com/matrix-org/synapse/issues/9937))
+
+
 Synapse 1.33.0 (2021-05-05)
 ===========================
 
diff --git a/changelog.d/9937.bugfix b/changelog.d/9937.bugfix
deleted file mode 100644
index c1cc5ccb43ae79c6274a99c92409a2c5ed8c3531..0000000000000000000000000000000000000000
--- a/changelog.d/9937.bugfix
+++ /dev/null
@@ -1 +0,0 @@
-Fix bug where `/sync` would break if using the latest version of `attrs` dependency, by pinning to a previous version.
diff --git a/debian/changelog b/debian/changelog
index b54d3f2bc6402597a4c8b9bd8d33b2aca29384c7..de50dd14ea802be5e251b8426f5dc6e0f5b0add5 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,9 @@
+matrix-synapse-py3 (1.33.1) stable; urgency=medium
+
+  * New synapse release 1.33.1.
+
+ -- Synapse Packaging team <packages@matrix.org>  Thu, 06 May 2021 14:06:33 +0100
+
 matrix-synapse-py3 (1.33.0) stable; urgency=medium
 
   * New synapse release 1.33.0.
diff --git a/synapse/__init__.py b/synapse/__init__.py
index 5eac40730a7719fdc2cbb39de4c52a6f0ba4aace..441cd8b33906d70a2b229e014cc07c40d8107898 100644
--- a/synapse/__init__.py
+++ b/synapse/__init__.py
@@ -47,7 +47,7 @@ try:
 except ImportError:
     pass
 
-__version__ = "1.33.0"
+__version__ = "1.33.1"
 
 if bool(os.environ.get("SYNAPSE_TEST_PATCH_LOG_CONTEXTS", False)):
     # We import here so that we don't have to install a bunch of deps when