The PHP community has released major update over a decade as PHP 7. PHP 5 brings many exited features like support of Object oriented programming and many related with that.
You guys may wonder why PHP community released PHP 7 just after PHP 5 why there is no PHP 6? Well requirement for PHP 6 were not defined clearly and most of the people not agreed with, so the project ground to the halt. Almost all the features defined for PHP 6 were already implemented in PHP 5.3 and it’s later versions of PHP 5. So we almost got everything, which was documented for PHP 6, when features set for a major release community decided to avoid confusion with dead project and skip to PHP version 7 with the major updates.