I have a test setup of Nextcloud in version 9.0.53. I followed the instructions in Test our new work-in-progress upgrader script
I tried to update to the beta channel, but when I open https://myserver/nextcloud/updater, it shows that current version is 9.0.53 and no update is available.
Next I tried daily. Update is available, I run the update script. finally, it asks if I want to keep maintenance mode (->no) and if I want to use the webinterface to proceed update (->yes). I go back to the login page and bad surprise:
Downgrading is not supported and is likely to cause unpredictable issues (from 9.0.53.0 to 9.0.52.0) Downgrading is not supported and is likely to cause unpredictable issues (from 9.0.53.0 to 9.0.52.0)
(message is shown twice)
I’m not sure what the updater script really installed (it was able to replace all files<-new creation date). The version.php shows:
<?php
$OC_Version = array(9,0,52,0);
$OC_VersionString = '9.0.52';
$OC_Edition = '';
$OC_Channel = 'daily';
$OC_VersionCanBeUpgradedFrom = array(8,2);
$OC_Build = '2016-07-22T23:01:04+00:00 3be8f7a369e91f8eed9fdd1df099e03a87001442';
Which seems to be identical with the daily-build from https://nextcloud.com/install/.
I’m not sure if this is an issue with the updater app (not working update to beta) and/or with the packaging of the daily build.
Edit: I reported the daily build version: https://github.com/nextcloud/server/issues/537