PHP 5.6 extended support has now officially ended (as converedd previously) and it will no longer be receiving updates nor security patches. As the last version of PHP5, PHP5.6 has been the longest supported version to date with active support starting in January 2015.
All is not lost as we PHP 7.2 is ready to go and offers both an increase in speed and continued support and security patches.
Not only is this available for Magento 2, but Magento 1 is also catered for as discussed here.