Hi, for an obvious reason, i currently need a way to have a php4 version. Is there a way to have it ?
Yeah very obvious Why would you need an ancient version that is end-of-life since 2008?!? Anything needing php4 should have been trashed years ago.
it's not easy to find sources (or i don't know how to search). Do you think i can make it available in ispconfig after ?
It is not hard to find at all https://museum.php.net/php4/ I don't think you should even attempt to install this on a production environment. If your goal is to port the application to an new PHP version you don't even need php4. But if you want to use it, do it in a dev environment, port the application to a modern php version and then deploy it in production.