I recognized, that OMV is not upgraded from 5.4.2-1 to 5.6.2. This is why salt-common and salt-minion are to old (> version 3000 is necessary):
apt policy salt-common shows:
salt-common:Installiert: 2018.3.4+dfsg1-6+deb10u2
Installationskandidat: 2018.3.4+dfsg1-6+deb10u2Versionstabelle:
3002.2+ds-1 500500 http://packages.openmediavault.org/public usul/main amd64 Packages
500 https://openmediavault.github.io/packages usul/main amd64 Packages*** 2018.3.4+dfsg1-6+deb10u2 990
990 https://debian.netcologne.de/debian buster/main amd64 Packages990 https://deb.debian.org/debian-security buster/updates/main amd64 Packages
100 /var/lib/dpkg/status
So i have to install version 3002.2+ds-1 500, but i don't know how (pinning wrong).
Any hints?