PHP Custom Session Handler Problems (PHP 7.1)

Culprit has been found. It turns out that session_start() doesn't like the read method of a custom session handler returning false if there's no session in existence. if anyone else gets a similar problem, if you've no session in existence, then the read method needs to return an empty string instead of either false or null.

The solution was found at http://php.net/manual/en/function.session-start.php#120589 i was looking at the the manual page for session_set_save_handler(), not expecting the solution to actually be in the comments section of the session_start() page.

I don't know why the change was made to what the session_start() method expects to get from the read method of a custom session handler