Details on this story have been trickling out for a while but things appear to be getting clearer with each new tidbit.
The basic news is this:
The current BMW 1-Series will be turned into a 2-Series to make room for a new FWD entry-level vehicle that will take up the 1er moniker.
So, that means BMW registering the 'M2' name in both Germany and the United States is intending to make sure they have a name for what will be the successor to the current 1-Series M.
Of course, a patent filing doesn't mean a model is in development, but taken together with previous reports it seems that a future 2-Series will be the continuation of the current 1-Series under a new series number.
Variants will include a 2-Series coupe (allegedly to be called F22), a convertible (F23) and an M2 performance model along with the standard 5-door hatch body-style version.