Proxmox VE 8 (Debian 12) Support endet August 2026. PVE 9 (Debian 13) In-Place-Upgrade-Leitfaden: pve8to9 Pre-Check, APT-Sources Bookworm→Trixie, dist-upgrade, Cluster Rolling Upgrade, VM-Kompatibilität (Machine-Version, virtio-Treiber), ZFS-Rollback-Szenario und häufige Probleme.