Upgrading to MacOS Sierra will break your SSH keys and lock you out of your own servers.
Quincy Larson

Why not have the user first login to the remove server using the old key before destroying it. Will the server log them out if the key on the local machine is changed? Just asking. It seems that instructing someone to remove the key without first instructing them to either login or make sure they at least have a way to log would have been a better idea. You instruct your readers to destory their key, then tell them they might need a friend.

One clap, two clap, three clap, forty?

By clapping more or less, you can signal to us which stories really stand out.