"Back" in inbox doesn't go back anymore. Instead it quits Aqua Mail
I have two accounts in Aqua mail. After starting Aqua mail, both of them are displayed. I open the inbox of one of the accounts. When I try to go back using the "back" button on the bottom of the screen, I do not get back to the screen which displays both accounts. Instead, Aqua Mail quits.
This behavior was different until one of the last updates. "Back" always resulted in going back to the screen which displays both accounts. Going back from there meant to quit Aqua Mail.
I recommend to implement "Back" how it was before. Inbox --> "Back" --> display the account overview screen.