PHP 5.3 is now supported by all major Linux distributions,
and has gained a lot of traction by projects like Symfony2, Drupal8 and Zend Framework 2.
We think that exciting new features in PHP 5.3 like namespaces and late static binding
can improve the way we and you code with SilverStripe.
On the other hand, only around a quarter of all web servers run it already,
and we want to provide an inclusive experience, as well as a smooth upgrade path.
Sources: http://w3techs.com/technologies/details/pl-php/5/all http://distrowatch.com