Upgrading from Nextcloud 20 to 21

After the upgrade, these are messages that were presented post-upgrade:

To fix the issues, I entered a terminal session and tried to execute the command below:

root@nextcloud:/usr/local/www/nextcloud/config # su -m www -c 'php /usr/local/www/nextcloud/occ config:system:set default_phone_region --value="AU"'
An unhandled exception has been thrown:
OC\HintException: [0]: Memcache \OC\Memcache\APCu not available for local cache (Is the matching PHP module installed and enabled?)

Oops! What’s going on here?! The fix is in this thread [SOLVED] Apcu Caching gives Error. It required config.php to be manually edited:

root@nextcloud:/usr/local/www/nextcloud/config # ee config.php

…and the following line:

'memcache.local' => '\OC\Memcache\APCu',

changed to…

'memcache.local' => '\OC\Memcache\Redis',

Once that’s done occ runs successfully.

root@nextcloud:~ # su -m www -c 'php /usr/local/www/nextcloud/occ maintenance:mode --on'
Maintenance mode enabled
root@nextcloud:~ # su -m www -c 'php /usr/local/www/nextcloud/occ config:system:set default_phone_region --value="AU"'
Nextcloud is in maintenance mode - no apps have been loaded

System config value default_phone_region set to string AU

root@nextcloud:~ # su -m www -c 'php /usr/local/www/nextcloud/occ db:add-missing-indices'
Nextcloud is in maintenance mode - no apps have been loaded

Check indices of the share table.
Check indices of the filecache table.
Adding additional size index to the filecache table, this can take some time…
Filecache table updated successfully.
Check indices of the twofactor_providers table.
Check indices of the login_flow_v2 table.
Check indices of the whats_new table.
Check indices of the cards table.
Check indices of the cards_properties table.
Check indices of the calendarobjects_props table.
Check indices of the schedulingobjects table.
Check indices of the oc_properties table.
root@nextcloud:~ # su -m www -c 'php /usr/local/www/nextcloud/occ maintenance:mode --off'
Maintenance mode disabled

Refreshing the admin screen, all warnings have disappeared.