However, after receiving the update to Android 7 yesterday, Tasker can still set DND to Priority as before, BUT it can no longer set it to None. After running the action DND mode is still set and showing as such in the notification bar.
The Run Log gives the action a status of OK.
Any suggestions on how to get Tasker to turn off DND mode on Android 7?
From the OP it sounds like you had the meanings of these two settings backwards.
BUT they're correct in my Tasks. They haven't changed in months.
Furthermore, my Samsung Galaxy S2 Tab has just got Android 7 too and the same problem occured.
FIXED IT though!
I wrote a test Task that just set DND and Flashed %INTERRUPT so I could screenshot it. But it worked fine. So it must have been something else in my other Task.
I found out that if you set DND to All, then immediately set Silent Mode to Off, this seems to prevent DND from being set to All. If you add a Wait of 2 seconds between them it works fine too.
So at least there's a work around.