diff --git a/CHANGES.md b/CHANGES.md
index bdeb614b9..206859cff 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,12 @@
+Synapse 1.33.0 (2021-05-05)
+===========================
+
+Features
+--------
+
+- Build Debian packages for Ubuntu 21.04 (Hirsute Hippo). ([\#9909](https://github.com/matrix-org/synapse/issues/9909))
+
+
 Synapse 1.33.0rc2 (2021-04-29)
 ==============================
 
diff --git a/debian/changelog b/debian/changelog
index fd33bfda5..b54d3f2bc 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,9 @@
+matrix-synapse-py3 (1.33.0) stable; urgency=medium
+
+  * New synapse release 1.33.0.
+
+ -- Synapse Packaging team <packages@matrix.org>  Wed, 05 May 2021 14:15:27 +0100
+
 matrix-synapse-py3 (1.32.2) stable; urgency=medium
 
   * New synapse release 1.32.2.
diff --git a/scripts-dev/build_debian_packages b/scripts-dev/build_debian_packages
index 3bb6e2c7e..07d018db9 100755
--- a/scripts-dev/build_debian_packages
+++ b/scripts-dev/build_debian_packages
@@ -21,9 +21,10 @@ DISTS = (
     "debian:buster",
     "debian:bullseye",
     "debian:sid",
-    "ubuntu:bionic",
-    "ubuntu:focal",
-    "ubuntu:groovy",
+    "ubuntu:bionic",   # 18.04 LTS (our EOL forced by Py36 on 2021-12-23)
+    "ubuntu:focal",    # 20.04 LTS (our EOL forced by Py38 on 2024-10-14)
+    "ubuntu:groovy",   # 20.10 (EOL 2021-07-07)
+    "ubuntu:hirsute",  # 21.04 (EOL 2022-01-05)
 )
 
 DESC = '''\
diff --git a/synapse/__init__.py b/synapse/__init__.py
index 319c52be2..5eac40730 100644
--- a/synapse/__init__.py
+++ b/synapse/__init__.py
@@ -47,7 +47,7 @@ try:
 except ImportError:
     pass
 
-__version__ = "1.33.0rc2"
+__version__ = "1.33.0"
 
 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