I'm on stock Android 7 with my Nexus 6P. Because I have a Pebble, I had "Smart watch enhancements" enabled, because, well, enhancements.
I have a custom config of Action buttons: "Delete, Mark read, Move to Spam", which worked well on Android 6 and before. However, ever since upgrading to 7 Nougat, AquaMail shows the default button configuration instead, until I disable the "Smart watch enhancements" checkbox. Then the custom buttons show up again in the normal notifications, but I don't get any integration with my Pebble.
Tried with various versions of AquaMail, currently using 1.6.4-dev4.
Let me know how I can help debugging.