diff --git a/CHANGELOG.md b/CHANGELOG.md
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--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -55,6 +55,7 @@
 
 ## Changes since v5.1.1
 
+- [#620](https://github.com/oauth2-proxy/oauth2-proxy/pull/620) Add HealthCheck middleware (@JoelSpeed)
 - [#604](https://github.com/oauth2-proxy/oauth2-proxy/pull/604) Add Keycloak local testing environment (@EvgeniGordeev)
 - [#539](https://github.com/oauth2-proxy/oauth2-proxy/pull/539) Refactor encryption ciphers and add AES-GCM support (@NickMeves)
 - [#601](https://github.com/oauth2-proxy/oauth2-proxy/pull/601) Ensure decrypted user/email are valid UTF8 (@JoelSpeed)