diff --git a/CHANGELOG.md b/CHANGELOG.md
index be6c956..c265bb3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Changelog
 
-## Unreleased
+## 0.4.0 (2023-11-13)
 
 ### Features
 
diff --git a/pyproject.toml b/pyproject.toml
index 2914980..216310d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "django-gov-notify"
-version = "0.3.0"
+version = "0.4.0"
 description = "A GOV.UK Notify flavoured Django email backend"
 authors = ["Nick Smith <nick.smith@torchbox.com>"]
 readme = "README.md"