Heya,
I just updated the forums to the latest and greatest beta of Flarum and switched over from PHP 5.6.x to PHP 7.0.x. I also changed the mail driver to use PHP’s built-in mailing function and successfully tested it a couple minutes ago. Hopefully you can now finally keep updated on posts via mail notifications. If you don’t, just… well… drop me a quick mail 
Thanks for your patience, keep in mind that Flarum is beta software (but I love it! 
)
Cya!