update after trying 4.9 preview 4:
The good news:
MSAA appears to be working out of the box!!!
The bad news:
I have a bug - upon starting the app for about 0.5 of a second the game is shown not in stereo - it then goes black for 0.5sec and after that is shown correctly in stereo. I don’t have any console commands (tested on a bare bones 1 sphere and a floor project).
We Can work around by showing nothing but a black screen for a second on begin play but not so nice …
I’m not sure if it’s related by all my old projects - including the ‘unofficial’ GearVRLighting demo uploaded on another thread by I think ex-employee JJ - crashes after showing the app briefly in non-stereo. So it looks like we need to re-create 4.7 projects as brand new 4.9 projects to work? (ie: the conversion does not work) -> probably some old config setting causing this??
The second bug which has always been there “For distribution”: Upon finding the app activity shortcut and starting the app that way it “crashes to desktop” with no relevant error messages shown in the Android Debug Monitor 
If this is not the correct way to test it could you let us know how?