According to a wiki announcement made on the PHPUnint GitHib repository, the next major version of the popular unit testing tool will only support PHP 5.6 and above.
According to our release process, PHPUnit must be compatible with all versions of PHP that are actively supported by the PHP project.
Active support for PHP 5.4 ended on September 14, 2014 and active support for PHP 5.5 will end on June 20, 2015. The active support for PHP 5.3 already ended on July 11, 2013. By the time PHPUnit 4.8 will be released, the only actively supported version of PHP will be PHP 5.6. The next version after PHPUnit 4.8 will not support PHP 5.3, PHP 5.4, and PHP 5.5 anymore. As PHPUnit follows Semantic Versioning the major version number must be incremented when the minimum required version of PHP is increased.
This will be a major change for many projects out there used to just fetching the latest version of PHPUnit for their projects. With PHP 5.3 and 5.4 making up such a major part of the currently installed versions, this could really help to push those hosts/companies using these unsupported versions for upgrades. It's good to see a prominent project like PHPUnit pushing the community to supported versions.