It had been working but after the last update, it force closes when I tap "record".

[Kimusoft]

Try changing the audio recording frequency from 'auto' to '44100 mono'.  I think this has a good chance of resolving the problem you're having with recording..

Directions (to change audio recording frequency):

Within the Ultra Voice Changer app, go to Menu->Prefs and try selecting one of the other audio recording rates, such as 44100 mono, and see if that works for you. Some devices incorrectly report what audio frequencies they actually record, which can cause issues when Ultra Voice Changer tries to autodetect them. Once you've selected the 44100 mono recording rate, you then need to make a new recording by pressing the record button within the app.