With the patent for the MP3 expiring, will anyone be required to license it? And if licensing becomes no longer an issue, will the games industry, especially mobile, migrate toward MP3?
Although MP3 licensing has always been muddy and unclear, as far as I’m aware (and I used to work at a company whose technology was based around audio files and playback) the licensing was always based on shipping an encoder or decoder.
Therefore simply using MP3 files does not incur licensing - but shipping a decoder might. This would either be on the side of Unity themselves (if a decoder library is built into the game engine) or the OS provider if Unity uses a system library.
In any case I don’t think it’s an issue now either way. But on the other hand there are superior libraries now anyway.