I thought I'd share my recent experience of customizing the php.ini file(s) associated with a particular setup through the ISPConfig admin panel. I run a small server for a handful of websites including a couple of Nextcloud installations on Ubuntu 22.04 LTS with the setup based on the Perfect server tutorial [since installing, the Ubuntu has been upgraded from 20.04 to 22.04 LTS]. The Nextcloud installations complained that opcache was misconfigured and the settings for opcache.memory_consumption and opcache.interned_strings_buffer needed to be increased. These were just warnings, but others have had significant difficulty clearing them. Now I know why. The problem relates to the way the 'Options' tab on the ISPConfig admin panel changes the php.ini file. Specifically, this tab changes the php.ini file in /var/www/conf/[#userid]. But there are other php.ini files in /etc/php/8.2/fpm (when running under php-fpm ver 8.2) and in related files linked from the conf.d subdirs of this folder. For some of the options, it's perfectly fine to make changes in the 'Options' tab, since the changes to the /var/www/conf/[#userid]/php.ini file will be adopted by the server. For other options, notably those related to opcache, you need to make the changes directly in the /etc/php/8.2/fpm subdirs. In the case of opcache settings, this is linked from /etc/php/8.2/fpm/conf.d/10-opcache.ini to /etc/php/8.2/mods-available/opcache.ini. You therefore need to make the required changes to opcache.memory_consumption and opcache.interned_strings_buffer in this file, and then the warnings go away. I though this might be useful to the forum for other customizations.