As of January 20, 2022, Ubuntu 21.04 is no longer supported. No more package updates will be accepted to 21.04, and it will be archived to old-releases.ubuntu.com in the coming weeks.
The original End of Life warning follows, with upgrade instructions:
Ubuntu announced its 21.04 (Hirsute Hippo) release almost 9 months ago, on April 22, 2021, and its support period is now nearing its end. Ubuntu 21.04 will reach end of life on January 20, 2022.
At that time, Ubuntu Security Notices will no longer include information or updated packages for Ubuntu 21.04.
The supported upgrade path from Ubuntu 21.04 is via Ubuntu 21.10. Instructions and caveats for the upgrade may be found at:
https://help.ubuntu.com/community/ImpishUpgrades
Ubuntu 21.10 continues to be actively supported with security updates and select high-impact bug fixes. Announcements of security updates for Ubuntu releases are sent to the ubuntu-security-announce mailing list, information about which may be found at:
https://lists.ubuntu.com/mailman/listinfo/ubuntu-security-announce
Since its launch in October 2004 Ubuntu has become one of the most highly regarded Linux distributions with millions of users in homes, schools, businesses and governments around the world. Ubuntu is Open Source software, costs nothing to download, and users are free to customise or alter their software in order to meet their needs.
Originally posted to the ubuntu-announce mailing list on Thu Jan 20 23:50:44 UTC 2022 by Brian Murray on behalf of the Ubuntu Release Team