NextCloud APCu not available for local cache

When trying to upgrade nextcloud, I get the following error

www-data@mail:/www/nextcloud$ php7.3 occ upgrade
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?)
www-data@mail:/www/nextcloud$ 

To fix this, you need to install APC cache.

apt install php7.3-apcu

For CLI, you need to edit PHP configuration file

vi /etc/php/7.2/cli/php.ini

at the end of the file, add

apc.enable_cli = 1

You can also enable apc for the current command with option

php7.3 -d apc.enable_cli=1 occ upgrade