As of yesterday, Jan 20th, 2017, PHP 5.6 will be no longer actively maintained, however It will still receive security fixes through December 31st, 2018.
PHP 7.0 and 7.1 are the only two versions that will be actively maintained this year and Laravel 5.5 will require PHP 7.0 once it’s released which is scheduled for July.
Here is a breakdown of PHP’s supported versions :
