Too early to confirm, but the word is that after MP-11 Starscream (the new smaller one), the next one could just be a redeco.... MP-11S Sunstorm.
Sounds like an odd choice, but MP-2 was just a redeco of MP-1.


And from the same source, the next Encore release (#23) is said to be a re-release of Sixshot... which was previously released as an "unlabeled" reissue in 2002 (as in, it was basically just a reproduction of the original packaging with no added badging like "Encore" on it).

Sunstorm is said to be out in May, Sixshot out in July.