You earn money with that? Damn, don´t understand that. PHP8 is out a bit. There are to many places you have really to work on.
Security has been on the first place for developpers and his customers. When the dev has costumers.
The setup is really terrible. The callback functions, are very frustrating with the returns. They don't offer any saving of the inputs. Always and always everything has to be entered from the beginning.
And please update the login session to a sh1 compatible format. I think this is standard today. Md5 has long ceased to be a concept for securely comparing anything or encrypting overly sensitive data.
Template Engine:
There are dozens of engines in PHP. You don't have to reinvent the wheel. But as soon as you try to feed several users and projects externally or internally, the whole system quickly becomes slow. Queries get bogged down. The APi and the SOAP backend then react with timeouts.
Plugins without added value. As long as you don't provide a plugin-capable core, all the plugins remain static and without much additional content. You could do much more
But otherwise, at least the current functions for smooth operation are included. The database support is far too extensive. Export and import of data in current formats works well.
Just my opinion on the free version
