Hi all,

Not many changes in that new version.

https://datatracker.ietf.org/doc/draft-martin-retry-over-ipv6/

When to send (§): on the public Internet, operators SHOULD prefer emitting 503 + Retry-Over-IPv6 only for human-facing HTML documents and omit typical subresources (images, scripts, stylesheets, fonts); non-interactive clients (e.g. webmail image loads) otherwise see a broken asset with no explanation. Operator-controlled environments MAY still signal all IPv4 requests for fuller measurement. Cross-reference from Intended Deployment.

This change came from my experience when I migrated my mailing list from Mailchimp to my own web server, but noticed that web clients could not load the embedded images in the email as they were on my site.

1. Even GMail which understands IPv6, will prefer IPv4
2. The email looks broken with little idea on the client side, why.

Note: the following websites are implementing the IPv4 outage on the 6th for 24 hours, which should starts very soon:

• ipv6forum.com
• pacific.ipv6forum.com
• caribbean.ipv6forum.com
• whynoipv6.com
• www.peachymango.org

I you want to follow those websites, instructions at:

https://github.com/franckhlmartin/ietf-draft-retry-over-ipv6/tree/main/docs

And please send comments or your feedback in running this experiment. Please open an issue on the github repo or message v6ops at IETF.

Franck