upgrade Proxmox VE 6 to 7

1.เพิ่ม rep
Open and edit repo list
# nano /etc/apt/sources.list
copy and paste:
deb http://download.proxmox.com/debian/pve buster pve-no-subscription

2. update pve6 
# apt update
# apt upgrade

3. ตรวจ upgrade
Check upgrade requirements
# pve6to7

4.ลบ ProxMox 6 Enterprise Repository
# rm /etc/apt/sources.list.d/pve-enterprise.list

5. update repositories to Bullseye
sed -i 's/buster\/updates/bullseye-security/g;s/buster/bullseye/g' /etc/apt/sources.list

6. Add new PVE Enterprise Repository
# echo "deb https://enterprise.proxmox.com/debian/pve bullseye pve-enterprise" > /etc/apt/sources.list.d/pve-enterprise.list

7.ตรวจความถูกต้อง
$nano /etc/apt/sources.list.d/pve-enterprise.list
$nano /etc/apt/sources.list

8.update and dist-upgrade
$ apt update
$ apt dist-upgrade

9.Reboot
$ reboot