diff --git a/CHANGELOG.md b/CHANGELOG.md
index 72179dc..e35e306 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,12 @@
-# Revision history for constrained-some
+# Changelog
 
-## 0.1.0.0 -- YYYY-mm-dd
+All notable changes to the constrained-some library will be documented in this
+file.
 
-* First version. Released on an unsuspecting world.
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [PVP versioning](https://pvp.haskell.org/).
+
+## Initial release: v0.0.1 _(2024-11-27)_
+
+### Added
+- Existentials `Somes` and `Somes1`