What music formats are supported by Apple devices and iTunes after the latest update?

What music formats are now supported for Apple devices and iTunes (for Windows)? The latest update in iTunes resulted in significant music losses. So far, I haven’t found a pattern among the losses - both owned music and purchased music.

I have to rebuild my library manually. And then decide what to do for the future. Meanwhile, this change is most annoying - especially without any warning.

[Re-Titled by Moderator]