After installing PHP 7.3 via the sury package (https://packages.sury.org/php/), Virtualmin recognises the new version (PHP 5.6 is standard with this distribution.)
However, when using the FCGId PHP script execution mode in the Website Options section, per default, it will not work, leading to 500 errors like these:
[core:error] [pid 19302] [client 22.214.171.124:42350] End of script output before headers: php.php
[fcgid:warn] [pid 19303] (104)Connection reset by peer: [client 126.96.36.199:41251] mod_fcgid: error reading data from FastCGI server
To fix this, one can follow this guide (https://www.virtualmin.com/comment/754860#comment-754860) to change the PHP execution path from
One thing to note is that on my server, the PHP 5.6 script has it correctly and references the right PHP CGI binary (
This should be done per default, since otherwise this introduces a new manual task to be done every time a new Virtual Server is created.