diff --git a/setup/release-notes/v2.2.0.md b/setup/release-notes/v2.2.0.md
index 14e0e8508..99738cfe3 100644
--- a/setup/release-notes/v2.2.0.md
+++ b/setup/release-notes/v2.2.0.md
@@ -23,3 +23,6 @@ description: SUSE Observability Self-hosted
 * Fixed issue where outgoing and incoming layers were reversed in the topology visualizer.
 * Make sure the 'available service endpoints' fires when there are pods which are not in ready state."
 * Only load related resources per type to avoid an error condition in the related resources drawer.
+
+### Breaking changes
+* The allowed usernames when using [file based authenticated](/setup/security/authentication/file.md) is restricted to alphanumeric characters and `_`.