They never tell us when things are going to release.
Upgrade to U1 now, get used to all things v8 and then upgrade to U2 when it ships. The process takes less than an hour.
Make sure you have backups of your current vCenter from the VCSA and also power it off and take a cold snapshot. Don't take a live one.
Then you have nothing to worry about if something goes amiss. Even if you went straight to U2, you'll still be using AD over LDAPS until you re-configure it to use Azure. So I see no benefit of waiting.
