Although I do my best to accommodate everyone, I have had to make the stance only to support PHP 7.1+. If you run a site with a PHP version older than this I highly recommend you upgrade to at least PHP 7.1. Older versions of PHP are no longer supported and may contain security issues.
How to determine your version of PHP
This is a handy plugin that will display your PHP version on WordPress Admin dashboard:
As stated on WordPress.org’s requirements page, WordPress recommend that WordPress is run on a server that supports PHP 7.4+.