Errors upgrading to Nextcloud 25.0.1

I can’t upgrade Nextcloud from the web-based updater for several months, I can only do it with occ upgrade in terminal.

Also, in the terminal the following error is thrown:

OCP\HintException: [0]: Memcache \OC\Memcache\APCu not available for local cache (Is the matching PHP module installed and enabled?)

which can be resolved with:
root@web:/var/www/nextcloud# sudo -u www-data php --define apc.enable_cli=1 occ upgrade

After the upgrade the default white theme doesn’t work (no icons on top are visible). I can only make them visible by changing to an another background.

Maybe apc.enable_cli = 1 in php.ini see issue

Same problem was here. I uninstalled the app Splash and after i reinstalled Splash it works again.