Learn how to upgrade and revert Proxmox from version 6 to 7 using UEFI boot and GRUB in this comprehensive tutorial video. Discover a fail-safe approach to server upgrades by creating a backup plan using GRUB and efibootmgr. Follow along as the process of converting a swap partition into a bootable Linux partition is demonstrated, allowing for a quick reversion to the previous version if needed. Gain insights into UEFI boot mechanics, EFI boot settings updates, and GRUB configuration. The video also covers volume management, including shrinking the original volume and creating a new one for the upgrade. By the end, you'll have a thorough understanding of how to safely upgrade Proxmox while maintaining the ability to revert changes in less than a minute if issues arise.