Looking at
Build Status dev
Source: Info about Fairphone FP2 - FP2
I got the feeling, that /e/ for the FP2 is not stable yet, but still a development build. Thus I was wondering when a stable release might be available. Now I recognized that for all devies the channel “dev” is stated. Could someone with more /e/-internal knowledge than me enlighten me please. 
And btw coming from an encrypted FP Open OS, is there anything to consider for updating? I saw the update description in the forum here, which seems to not make any difference to a backup + factory reset and flash (if I have to back up and recover all app data manually anyway).