Changes to PlayMusic() API Call in 7.0?

Hi there, just curious if anything about the PlayMusic() API function was changed that would cause it to no longer work with custom MP3 files in an AddOn folder.

I have an AddOn written that stopped working after the patch today, and I've debugged to the point that it can only be this specific call anymore. Calling PlayMusic() with a music file in the AddOns folder also does nothing when run through a /script command in-game. Here's the bit of code in question:

PlayMusic("Interface\\AddOns\\SimplyMusic\\Music\\" .. track .. ".mp3");

Worth noting, playing existing game music (i.e. classic login screen music) works just fine when called through an in-game /script command.