Re: Mighty Rom 4.8 no sound for email notification
 

I found a resolution. If you use the old version of Seven instead of the new one the email notifications work perfectly. The old file name is/was "seven Beta Email Client". I have it but I'm currently tethering and to upload it would be super slow.

Make sure when the app pops up asking if you would like to upgrade to the latest version you choose later.

Re: Mighty Rom 4.8 no sound for email notification
 

You don't need to install the old version, here's a workaround:

Under the Notifications tab in the Sounds and Notifications menu, select New Email Message. Make sure "Play Sound" and "Display Message on Screen" are checked.

Fixed. ;)