Thanks for the report. It's a known issue, IPv6 should be back when we manage to move http.kali.org to a new machine. Could be in a few weeks, or in a few months, no ETA.

You can use kali.download instead in your sources.list. It's the Cloudflare CDN, it has IPv6 support I believe. Does that work for you?

Yes, it works. Wish you a smooth server migration.

Thank you very much. Nice profile picture that you have here.

Closing this issue!