Ubuntu 21.04 will reach end of life on January 20th, 2022. At that time, Canonical will stop offering updates for the Hirsute Hippo release.
Powered by Linux kernel 5.11 and built around the GNOME 3.38 desktop environment series (with support for GNOME 40 apps), Ubuntu 21.04 (Hirsute Hippo) also introduced PipeWire support, nftables as the default firewall backend, support for smart card authentication, and a redesigned Yaru dark theme.
Because it was not a long-term support (LTS) release, it will reach end of life on January 20th, 2022. All users are urged to upgrade to Ubuntu 21.10 (Impish Indri) as soon as possible!