diff --git a/README.md b/README.md
index db79373..938684b 100644
--- a/README.md
+++ b/README.md
@@ -40,6 +40,7 @@ including image thumbnails), including optional [HTTPS](https://mailpit.axllent.
 - [Link check](https://mailpit.axllent.org/docs/usage/link-check/) to test message links (HTML & text) & linked images
 - [Spam check](https://mailpit.axllent.org/docs/usage/spamassassin/) to test message "spamminess" using a running SpamAssassin server
 - [Create screenshots](https://mailpit.axllent.org/docs/usage/html-screenshots/) of HTML messages via web UI
+- `List-Unsubscribe` syntax validation
 - Mobile and tablet HTML preview toggle in desktop mode
 - Advanced [mail search](https://mailpit.axllent.org/docs/usage/search-filters/)
 - [Message tagging](https://mailpit.axllent.org/docs/usage/tagging/)