Thanks! I am actually using RunUO, and not the newest client. I am not sure the version, but it goes up to the Stygian Abyss. I actually replaced the original Config file with a remastered version of the original UO soundtrack, and further modified the Config file by adding a few tracks to it, though I did this by replacing unused track slots, rather than adding any new numbers to the config file. I have not had any issues so far. I suppose I can try it on a test server and see what happens
[doublepost=1522420128][/doublepost]As an update, I tried adding some additional MP3, putting them in the Config file after the 87 listed (88, 89, 90, etc), and adding them to various regions in Region.xml. For some reason they are not recognized and do not play when entering the region. I assume this is a client thing. They do work when I replace an existing track in the Config with that file name. This will reduce the amount of music I wanted to add, but still leaves 24 or so unused tracks I can replace. Thanks for the help!