Philip Hazel, the man behind the Exim MTA takes his leave:

Just so you all know: this is my last day at work before retiring. I am
about to unsubscribe from the exim-users list. However, I will stay on
the exim-dev list for the moment and I am continuing to maintain PCRE.

It's been fun interacting with all you over the years!

It is a shame to see him go. He created one of the best documented and best functioning programs that exist.