It's really just an iOS issue. Apps can't run in the background to check mail and give notifications. So you need to check the mail on the server and send a n

It's really just an iOS issue. Apps can't run in the background to check mail and give notifications. So you need to check the mail on the server and send a new mail notification independently of the app. The weird side-effect of this hack is that you get a notification of a new email, then you open the Mailbox app and it has to go retrieve the new email from the server.