This rumor is confirmed by best sources. So do not take it with a grain of salt but as an almost 99% certain fact. The first week of February Olympus will announce the new E-M5 MarkII which will have one new unique feature in the OMD range:
The camera has a 16 Megapixel sensor that can shoot up to 40 Megapixel by shifting the sensor (in up to 8 frames of single shots).
So just like HDR shoots get combined to increase the dynamic range the new Olympus sensor will shift of 1 pixel for every shot and than combine the pictures to increase the resolution. This will work perfectly for landscape pictures a bit less perfectly on fast moving subjects.
For the rest the E-M5II will use the same E-M5 sensor so there is no improvement there :(