diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 3c07e4b9..37729cda 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -2,6 +2,17 @@
 Change history
 ==============
 
+2.x (TBD)
+------------------
+
+**New features**
+
+* made user emails unique to prevent two users logging in with the same email, causing an error
+
+.. warning::
+    User email addresses will now be unique on a database level. The database migration will fail if there are already
+    two or more users with the same email address. You must ensure this is not the case before upgrading.
+
 2.2.0 (2024-06-27)
 ------------------