Looking at the log from when the new version started up, it says that the "receipt is not grandfathered due to receipt version"
I've been a LONG time customer, and this copy has been upgraded all along the way, but has always worked right up until this beta 11 tonight.
From helper log:
Sat Feb 11 21:24:56 2017| 660011 [HELPER:(Main Thread):] M applicationDidFinishLaunching: | Starting 1Password mini 6.6.BETA-11 #660011 built Feb 11 2017 16:13:09. Running from: /Applications/1Password 6.app/Contents/Library/LoginItems/2BUA8C4S2C.com.agilebits.onepassword4-helper.app
Sat Feb 11 21:24:56 2017| 660011 [STORE:(Main Thread):OPAppStore] S receiptVersionIsGrandfathered: | Receipt is not grandfathered due to receipt version: (null)
1Password Version: 6.6 Beta 11
Extension Version: 4
OS Version: OS X 10.12.4
Sync Type: Dropbox