upgrading php version

hey im currently running laravel 5.3 and php version 5.6 but i read today this 'As of yesterday, Jan 20th, 2017, PHP 5.6 will be no longer actively maintained, however It will still receive security fixes through December 31st, 2018.'

how would i upgrade from php version 5.6 -> 7.0 is this an easy task ? or is it something i shouldnt worry about?