NextcloudPI Armbian 21.08.8 with Linux 4.14.222-odroidxu4 - Upgrade

I am running NextcloudPi on Armbian 21.08.8 with Linux 4.14.222-odroidxu4.
On ssh login, the warning appears: No end-user support: built from trunk
In the forum, i read about Armbian 21 with Linux 5.12
My question is, have i to update the linux system?
How can it be done?

  1. backup Nexcloud with ncp-backup
  2. install new ncp-image
  3. restore Nextcloud with ncp-backup
    Is there a easier way?