Lubuntu 21.04 (Hirsute Hippo) was released April 22, 2021 and will reach End of Life on Thursday, January 20, 2022. Will be no further security updates or bugfixes released.
We highly recommend that you update to 21.10 as soon as possible if you are still running 21.04.
After January 20th, the only supported releases of Lubuntu will be 20.04 and 21.10, and all other releases of Lubuntu will be considered unsupported, and will no longer receive any further updates from the Lubuntu team.