What’s the Oldest Version of Windows I Can Dual Boot with Linux?

Have you considered using virtualization instead? Tools like VMware Workstation or VirtualBox can let you run any version of Windows without messing with your main setup. I've had great experiences running multiple VMs, including Windows 95 and my favorite, Windows XP, which still supports lots of classic software and games.

My setup runs Linux Mint alongside various Windows versions dating all the way back to Windows 98. A cool method I used was to partition the drive using GParted for each OS — FAT16 for MS-DOS and NTFS for newer Windows versions. For some of the older versions, like Windows 1.0, you can install it using DOS, but I usually recommend sticking with Windows 98 since it's more functional. Just make sure to have the right bootloader set up like EasyBCD to manage everything smoothly.

Definitely back up your important files before trying anything, not just for this project but to prevent data loss from hardware issues or malware. If you're determined to dual boot, you can go pretty far back with Windows, but it gets tricky with certain versions. A good tip is to install the oldest version first and work your way up. I found that if you install Windows Vista or 7 last, they'll still recognize XP and add it to the boot menu. However, XP won't detect the newer versions, so you might need some additional tweaks with something like BCDedit to sort the boot options.