Clients (most notably SpringLobby & my personal client(s) built on UberserverClientCore) that have implemented the b compat flag will fail to connect, due to expecting additional data in the BATTLEOPENED command from the server.
The lack of support for u is less consequential - since it is only an optional message sent to hosts when a user joins to let them decide whether the user may join the battle.
Clients (most notably SpringLobby & my personal client(s) built on UberserverClientCore) that have implemented the
bcompat flag will fail to connect, due to expecting additional data in the BATTLEOPENED command from the server.The lack of support for
uis less consequential - since it is only an optional message sent to hosts when a user joins to let them decide whether the user may join the battle.For reference: Spring lobby protocol description