A major complaint about Apple Music when it rolled out was that it used a metadata-based matching system, which sometimes caused it to incorrectly match songs in users’ music libraries with Apple’s database. Jim Dalrymple reports for The Loop, that:

Apple has been quietly rolling out iTunes Match audio fingerprint to all Apple Music subscribers. Previously Apple was using a less accurate metadata version of iTunes Match on Apple Music, which wouldn’t always match the correct version of a particular song. We’ve all seen the stories of a live version of a song being replaced by a studio version, etc.

According to Dalrymple, the audio fingerprint matching system that Apple is slowly rolling out to Apple Music is the same system that has been available to customers who subscribe separately to iTunes Match. The new matching functionality is being added by Apple at no additional cost to Apple Music subscribers, which means that if you previously subscribed to Apple Music and iTunes Match, there should be no reason to renew your iTunes Match subscription when it expires. As Jim Dalrymple points out, however, you may want to be sure that the new system is working properly before letting Match expire.