diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4dd76c0e..fcca0cd3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,9 +14,14 @@ The most noteworthy change of this release is the update of the container's base
 
 - **Updated base image to Debian 12** ([#3403](https://github.com/docker-mailserver/docker-mailserver/pull/3403))
   - Changed the default of `DOVECOT_COMMUNITY_REPO` to `0` (disabled) - the Dovecot community repo will (for now) not be the default when building the DMS.
+    - While Debian 12 (Bookworm) was released in June 2023 and the latest Dovecot `2.3.21` in Sep 2023, as of Jan 2024 there is no [Dovecot community repo available for Debian 12](https://repo.dovecot.org).
+    - This results in the Dovecot version being downgraded from `2.3.21` (DMS v13.3) to `2.3.19`, which [may affect functionality when you've explicitly configured for these features](https://github.com/dovecot/core/blob/30cde20f63650d8dcc4c7ad45418986f03159946/NEWS#L1-L158):
+      - OAuth2 (_mostly regarding JWT usage, or POST requests (`introspection_mode = post`) with `client_id` + `client_secret`_).
+      - Lua HTTP client (_DNS related_).
   - Updated packages. For an overview, [we have a review comment on the PR that introduces Debian 12](https://github.com/docker-mailserver/docker-mailserver/pull/3403#issuecomment-1694563615)
     - Notable major version bump: `openssl 3`, `clamav 1`, `spamassassin 4`, `redis-server 7`.
     - Notable minor version bump: `postfix 3.5.23 => 3.7.9`
+    - Notable minor version bump + downgrade: `dovecot 2.3.13 => 2.3.19` (_Previous release provided `2.3.21` via community repo, `2.3.19` is now the default_)
   - Updates to `packages.sh`:
     - The script now uses `/etc/os-release` to determine the release name of Debian
     - Removed custom installations of Fail2Ban, getmail6 and Rspamd