diff --git a/SUBSONIC.md b/SUBSONIC.md
index 65f8b8ed..7fd8007f 100644
--- a/SUBSONIC.md
+++ b/SUBSONIC.md
@@ -75,6 +75,7 @@ The following extra fields are implemented:
 * [getPodcastEpisode](https://opensubsonic.netlify.app/docs/extensions/getpodcastepisode/)
 * [HTTP form POST](https://opensubsonic.netlify.app/docs/extensions/formpost/)
 * [Index based Queue](https://opensubsonic.netlify.app/docs/extensions/indexbasedqueue/)
+* [Sonic similarity](https://opensubsonic.netlify.app/docs/extensions/sonicsimilarity/)
 * [Transcode offset](https://opensubsonic.netlify.app/docs/extensions/transcodeoffset/)
 * [Song Lyrics](https://opensubsonic.netlify.app/docs/extensions/songlyrics/)
 * [Transcoding](https://opensubsonic.netlify.app/docs/extensions/transcoding/)