> A standard protocol with nonstop changing profile requirements at LE's whim. Who's going to keep updating the software every 3 months to keep up?

It really doesn't change that often. And whether this is a "breaking" change is something that's debatable (you shouldn't hard-code the cert lifetime, but I suspect many programs do, so de-facto it may or may not be a breaking change).

If you look at the Go implementation for example (https://github.com/golang/crypto/commits/master/acme), then there haven't been any major changes since it was first written in 2018: just bugfixes and basic maintenance tasks. Maybe I missed a commit but it certainly doesn't require 3-month update cycles. You can probably take that 2018 code and it'll work fine today. And since it doesn't hard-code the 90 days it will continue to work in 2028 when this change is made. So it's more "you need to keep updating the software every decade to keep up".