I am coding in a Windows platform, then I hosted it in a Linux platform, then some codes did not work as it should be. So I am curious if this is normal or I just have an error on my part. Both PHP versions on Windows and Linux are PHP 7.1.1.
They will not all work the same. As PHP has matured it's deprecated features and added new ones. Simple code, and code designed for maximum compatibility should run on a range of versions - sometimes all versions, but it is very common to come across functions which require a minimum version - somewhat less common to find functions that don't work in newer versions (but often require supressing debug messages and/or yweeking configs to make it work)
I was learning PHP back in my college in Linux environment. Then for my project I used Windows on my home, only to find later that it is unusable on my campus lab.
The problem lies in how Linux treats "everything" as case-sensitive, while Windows quite lenient in what should be case-sensitive.
Fixing the code to consider case-sensitive parameter, class, and function makes my application work again.