PHP 5.3 introduced namespacing, it is a naming convention for classes that avoids naming conflicts. Composer helps by allowing the use of multiple packages that may have the same class names. It offers the ability to shorten long locations of class names using a alias to the directory path.
PHP 5 introduced autoloading which removed the requirement to keep including class files at the top of your working file. Autoloading also has a standard known as PSR4 which is used to define how autoloading should be used.
A look at the modern way to work with PHP which will allow us several advantages over the commonly used method of just having several includes throughout your code. One of which is the ability to manage our project library versions and dependencies.