According to a rumor posted on 43rumors today, the new Panasonic DMW-LVF2 electronic viewfinder will not work with current GF series cameras. The 1.44 million dot EVF would have issues transferring an increased amount of data to the older cameras.

I have been told the LVF2 has completely different physical connections. This is pity. I don’t know yet if the reason behind that is that the “old” GF connections could not be used to transfer a higher amount of data for the viewfinder or if that is another move from Panasonic to sell more GX1 cameras.

http://www.43rumors.com/ft3-next-bad-news-new-panasonic-dmw-lvf2-will-not-work-on-current-gf-cameras/

If true, this thing might not sell quite as well as Panasonic may have originally intended.