This response to my request is clearly non-confidential, so I’m going to share it:

Alex (ZeroSSL) Mar 16, 2026, 11:07 GMT+1

Hi - thanks for reaching out. We are working on expanding the support for IPv6, including certificates for IPv6 addresses as well as for validation. Unfortunately - this is not something we can do right now or in the near future but it is on our roadmap.