php_versions []

PHP Versions are fully supported for 2 years.
After 2 years the version will then be updated for critical security risks only for 1 year
It is then fully un-supported

PHP Version	Supported Until	Critical Security Updates
5.3 Released 01.01.12	2014	NOT SUPPORTED
5.4 Released 01.03.12	14.09.14	Until 14.09.15
5.5 Released 20.06.13	10.06.15	Until 10.07.16
5.6 Released 28.08.14	28.08.16	Until 28.08.17

Source: http://php.net/supported-versions.php