The new Olympus OM-D E-M10 Mark II camera that was announced earlier today still has a 16MP sensor. In an interview with Amateurphotographer, Olympus representative mentioned that we may see higher megapixel MFT cameras in the future:
Although Olympus currently uses a 16MP sensor, with future technology advances it might be possible to produce a model with a higher resolution.
The Panasonic GX8 MFT camera already has a 20.3 MP Digital Live MOS sensor.