Fixing the Devuan update issue....

The Devuan signing keyring five-year life expired unnoticed on the 3rd September. The developers were fairly fast to provide a new keyring, but to bring it 'live' DOES require manual intervention by the user, and cannot be invoked/installed by standard 'apt' usage. Two methods in this video, take-your-pick!
And good for 'LurcherOS', 'KDEvuan', 'Miyobang', 'PeppermintOS', and out-of-box Devuan of course...
Be safe!