Problems Update (currently in process)

Good day,
I wanted to upgrade my Nextcloud from an old (25.x.x) version to the current one. However, when I click on Update only comes:

Step 5 is currently in process. Please reload this page later.

This has been there for almost 2 weeks. So really only the text as text. There is no HTML, no CSS and nothing else. Do you have an idea ?

Thanks in advance

Try this:

Step 1

Delete this folder:

nextcloud/data/updater-$instanceid

(instanceid is defined in your config/config.php)

Step 2

Run the updater by commandline, this way:

sudo -u www-data /usr/bin/php -d memory_limit=512M -f /var/www/nextcloud/updater/updater.phar

(Adjust the paths and web server user to your circumstances)

Much luck.