I've been GM'ing Mummy's Mask for the past 2 months, and UDL has completely screwed with my players' computers. Massive lag, no visuals whatsoever (can't even see their own token), and various other things cropped up when we were using it. Legacy works just fine, and even works better than UDL in some ways. It's fine if you don't add support, just keep it as is and many players will still be able to play.