I just updated from 4.6b5 to b6 on my iPad Air running iOS 8 b4. As soon as I start it up it throws a "Build Expired" modal dialog. I also tried uninstalling it and reinstalling, same issue.
I saw the same thing, asking the team to pull the build and/or issue a quick fix soon.
Ahhhh also having this issue. Hopefully a fix comes soon! Thanks for working so fast on it!
We've pulled b6, you should reinstall beta 5 from here.
And b7 was just pushed out. All is good.
Thanks, I was just about to tell you guys beta 7 is out now. :P