diff --git a/CHANGELOG.md b/CHANGELOG.md
index ec50b4d..20cb0bb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,4 @@
-# v0.4.0 (unreleased)
+# v0.4.0 (2023-01-29)
 
 * Dropped support for using a custom maubot API base path.
   * The public URL can still have a path prefix, e.g. when using a reverse
diff --git a/maubot/__meta__.py b/maubot/__meta__.py
index 260c070..6a9beea 100644
--- a/maubot/__meta__.py
+++ b/maubot/__meta__.py
@@ -1 +1 @@
-__version__ = "0.3.1"
+__version__ = "0.4.0"
diff --git a/setup.py b/setup.py
index a4a16e1..51687cc 100644
--- a/setup.py
+++ b/setup.py
@@ -53,6 +53,7 @@ setuptools.setup(
         "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: 3.10",
+        "Programming Language :: Python :: 3.11",
     ],
     entry_points="""
         [console_scripts]