We announced it today:
let me add:
If you want Nextcloud 14 but prefer to use the updater, note that it will take time before Nextcloud 14 is available there. We roll out incrementally, that is, today only 20% of the Nextcloud installations gets notified. If no problems are found, we will add another 20% or so later this week and probably go full out next week. Patience, or manual installation!