@dalias
Per this blog post, at least let's encrypt is rolling it out now in the next couple months:
https://letsencrypt.org/2026/02/18/dns-persist-01
> Support for the draft specification is available now in Pebble, a miniature version of Boulder, our production CA software. Work is also in progress on a lego-cli client implementation to make it easier for subscribers to experiment with and adopt. Staging rollout is planned for late Q1 2026, with a production rollout targeted for some time in Q2 2026.