Here is a roundup of rumors about what we can expect in the near (and distant) future:
Announcement in late Summer (90% certain)
Same E-M1II sensor with 121 cross-type phase detection pixels. (60% certain)
New processing engine (90% certain)
Lighter, more plasticky but still weather sealed body (60% certain)
Same BLS-50 battery of the PEN and E-M10 camera series (60% certain)
line is dead :(
(FT3) Will Panasonic announce a new ultracompact Lumix GX880 by end of this Summer? (article here).