Incorrect required version

Hi Developers,

I just wanted to bring your attention to this support thread:
https://wordpress.org/support/topic/stripe-integration-10/

It appears that the plugin doesn’t work on at least WordPress 4.3 because it uses the wp_doing_ajax() function. From what I can tell this wasn’t introduced until 4.7. As such I believe the required version of your plugin should be updated to 4.7.