Hello all.
Just tried to update to NC 12 Beta3 but to my surprise the update button does not work. Nothing in the logs. Any clues?
That’s a known issue when you are coming from beta1 or beta2…
Ah. Good to know. Thanks Soko.
“sudo -u www-data php updater/updater.phar” works.
Thx for the solution folks 
that error drove me crazy 
If I run the above file then it likes to update me to 12.0.0 ? Is that correct? I’m expecting to get updated to 12.0.B3 or something like that? see below:
root@nextcloud:/var/www/html/nextcloud# sudo -u www-data php updater/updater.phar
Nextcloud Updater - version: v11.0.3-19-g3e2d9de
Current version is 12.0 beta 2.
Update to Nextcloud 12.0.0 available. (channel: “beta”)
Following file will be downloaded automatically: https://download.nextcloud.com/server/prereleases/nextcloud-12.0.0.zip
Steps that will be executed: