Glad you're fine with PHP. I find every single version upgrade, even a minor one, and I end up with library code calls that stopped working. From 3 to 4 to 5, to 7 (yeah, i skipped 6 and just let my crap rot for a time), every tiny upgrade and some library changed significantly enough that I had to spend hours fixing it.
Even then I'd think I'd fixed it to the right version on my home server, copy the code to the prod host, supposedly on the same php version, and yet I still had issues (specifically with the MySQL layer).
Then there's the matter that having gotten stuff to work with a particular library, the library is deprecated for security risks, isn't going to get fixed and I have to rip it out and replace it with something else (if that something else even exists).
So yeah, back-end has just much versioning crap and loss of backwards compatibility that the front-end does. The engine may be fine, but the libraries are a moving target just as much as any other language. You may have somehow avoided it with the libraries you've used. I've yet to be so lucky, and pretty much gave up on any future PHP 'cause I just don't care to keep up with it.
Even then I'd think I'd fixed it to the right version on my home server, copy the code to the prod host, supposedly on the same php version, and yet I still had issues (specifically with the MySQL layer).
Then there's the matter that having gotten stuff to work with a particular library, the library is deprecated for security risks, isn't going to get fixed and I have to rip it out and replace it with something else (if that something else even exists).
So yeah, back-end has just much versioning crap and loss of backwards compatibility that the front-end does. The engine may be fine, but the libraries are a moving target just as much as any other language. You may have somehow avoided it with the libraries you've used. I've yet to be so lucky, and pretty much gave up on any future PHP 'cause I just don't care to keep up with it.