Mega Man Legacy Collection 2 version 184.108.40.206 is available now on PC and PS4. Although no official notes were included with the 1.3GB patch, players did notice the "Licenced by Nintendo" line is no longer attached to Mega Man 7's copyright notices.
UPDATE: Mega Man 9 and Mega Man 10's music is not fixed. BGM is still quiet and, in some instances, there's no sound at all (PC version). Other than that, the patch appears to be more or less targeted at minor bug fixes. If you happen to notice anything else, shoot me a message.
Thanks to OKeijiDragon, MechaGS and BFeely for the info.