How to change PHP-FPM and PHP-CLI Version if Apache is Not Installed

[pksh71]

Hi, I have installed myvestacp on Debian 10 with no apache ie(NGINX+PHP-FPM) only.
it comes with php-fpm 7.3 i want to change it to either 7.1 or 7.4.
How can I do it and how can I verify that changes are correctly made.

[myVesta]

viewtopic.php?f=18&t=151&p=426#p426