functions have different cases about yakpro-po

[pk-fr]

Hi Sercan,
Thanks for using yakpro-po ... please star it if you like it...

It is a feature, not a bug!

http://php.net/manual/en/functions.user-defined.php

Note: Function names are case-insensitive, though it is usually good form to call functions as they appear in their declaration

yakpro-po modifies case of items that are case insensitive in order to increase obfuscation!

as commented in the source code :

// case-sensitive:      variable names, constant name, array keys, class properties, labels 
// case-insensitive:    function names, class names, class method names, namespaces, keywords and constructs 

[pk-fr]

I just saw you already stared it ;o)

[sercankd]

But its a problem for me, since those two files are connected eachother. One on the left have different case and other trying to call it with different case. It gives errors like function not found etc.

[pk-fr]

your problems cannot be related to case ...
try a little code like this to be convinced...:

<?php
    function hello() { echo "hello\n";}
    for($i=0;$i<3;++$i) HeLlO();
?>

https://3v4l.org/nqXgC : online test for above code for many php versions