Is there a minimal PHP API VERSION that I need to use?

I inherited PHP Monerisapi code and am using the testaccount store2 with yesguy, but only very few valid transactions get through.

We are also using it in a production environment and there it seems to be working fine all the time.


Looking into the 'dated' code, I see mpgClasses.php with "API_VERSION" => "PHP - 2.5.2"

Doing some searches "API_VERSION" or "VERSION" on your forum did not come up with any useful results.

Maybe I need to download an updated set of PHP files from GitHub ? Or should this version be running fine too? I assume it is not referring to my local PHP version?