Same here, the list of beta branches is empty.
I didn't encounter any starting issues after the update. The only effect of the update is, that CDLCs don't start playing. They are properly listed, they play properly when opened from the list. After start the amps are loaded and the guitar input works OK. There is no fret-board, no tablature and no menu/key hints.
It feels like if they have added something during loading, expecting something in the song data, which the CDLCs don't have.
Original songs and DLCs play without problems.