Coding languages like all software has versions. These versions offer improvements, and changes over time. This means that functions that work in some versions do not work in others. So you need to verify which version of PHP code has been written for, and also think about using common functions in your code to prevent issues with running it on new versions of PHP.
elseif statements allow you to check to see if any of a number of conditions are true before failing out to the else in an if statement.
The pathinfo() function allows you to turn a filepath into an Array and then interact with the keys of the Array. You can grab the Filename, Extension, Folder Name and Basename. pathinfo() https://www.php.net/manual/en/function.pathinfo.php https://www.w3schools.com/php/func_filesystem_pathinfo.asp pathinfo.php