Airmail for Mac has just been updated to version 1.1 and brings with it a huge list of new features including official Exchange support, POP3 support, the ability to redirect mail, and more. Unfortunately, the update also seems to be causing headaches for some users who say since updating they haven't been able to receive mail at all.
Issues aside, the 1.1 update to Airmail brings a tremendous amount of features that make it hard to pass up. Aside from general Exchange support and POP3 account support, there's also support for Outlook, Hotmail, and Live support. Lots of message support has been added too and new features such as an activity monitor.
I personally haven't experienced any issues with the 1.1 update but other members of our staff have. If you've already updated and don't seem to be receiving mail, I'd recommend trying to delete an account and re-add it. If that still doesn't fix the issue, uninstalling and re-installing Airmail may work.
If you've had this issue, let us know in the comments. If you managed to fix it, let us know what worked for you! If you haven't updated just yet, hold off if you can until a potential fix is released.