The off-air MHEG screens for CBBC and CBeebies have changed today. The previous red screens with a list of all of the BBC channel numbers have been replaced by screens with the channel logo at the top and a black background for CBBC, light blue for CBeebies, with text advising the viewer that programmes from the channels can be watched on BBC iPlayer.
I would not be surprised if the BBC Three and BBC Four off-air screens changed tomorrow (assuming they didn't today).