NC Update shows 22.2.0 but 21.0.5 is installed

i have NC 21.0.5 installed. The Updater shows me the availability of 22.2.0. Is 21.0.5 the end of the stable tree, or is that a failure?

The support of Nextcloud 21 ends Februar 2022. Why to change to Nextcloud 22?

I dont want to change, but NC shows me 22.2.0 as Upgrade Version.

There are new features and dependencies in the apps.
Also security reason. You get no patches in old versions.

Perhaps you can use your nextcloud the next one or two years.
But if you then must upgrade than it perhaps not works.