This is the first image of the almost final version of the upcoming new Olympus 300mm f/4.0 IS PRO Zuiko lens. As you can see Olympus added in lens stabilization as there is a new IS on/off switch. In short here are some features sent to me by an anonymous source:
1) The same retractable lens hood design as 40-150mm
2) minimum focus distance: 1.4m
3) IS on/off switch
4) focus limiter switch
Thanks to the anonymous source who sent me this!