Upgrading to the lates Nexcloud Version 21 via /usr/ports and make results in an error as shown below, when one would like to call the upgrade procedure via CLI. The error arisen from the latest ort upgrade seems to be related to php as searching the net indicates, but recompiling all requisite ports for nextcloud and also additinally recompiling all installed php74 ports and php74 itself via portmaster -f do no mitigate or solve the problem. Also, rising the amount of memory in memory_limit in etc/php.ini results in a accordingly risen "Allowed memory size of ..." number shown in the error below, reflecting the exact configured amount of memory in bytes:
# su -m www -c "php occ upgrade"
PHP Fatal error: Allowed memory size of 536870912 bytes exhausted (tried to allocate 266240 bytes) in /usr/local/www/nextcloud/lib/private/AppFramework/Utility/SimpleContainer.php on line 133
The problem has been introduced due to a "memcached" entry in config/config.php. Removing this entry (following some similar problem's mitigations I've found on the net) solved the specific problem.