What is PHP?
PHP stands for Hypertext Preprocessor, this is an open-source programming language that runs on the web server. According to W3Techs, PHP is used by over 79.1% of all the websites that use a server-side programming language. Basically every 8 out of 10 websites you visit are most likely utilizing PHP in some form. Of course PHP plays a very vital role in the WordPress ecosystem, as the entire CMS is built on PHP.
The life cycle of PHP
All of the PHP versions have a life cycle of around three years. After that period of time they are no longer supported.Read more on the PHP Version and WOrdpress