Php 5.6 reached end of life support and this means that it will not receive anymore any security update. If you, like me, run a site with WordPress or any other technology based on PHP you should consider moving to PHP 7 as soon as possible. This is needed to avoid having a bad surprise if someone discover a new security bug and he will use to own your site.
In this article you can find some interesting information and you can verify that moving to PHP 7 will probably made your site to go faster.
Since a compromised site can be used to do phishing or to host malicious scripts, it is a good habit keeping up upgrading your WordPress site and PHP version used by your blog.