[ethagnawl]

I haven't used Windows seriously in 20+ years, so I don't know, but did any of those upgrades also require hardware (not RAM or disk space) upgrades?

[michaelcampbell]

Nothing that Microsoft is demanding like the 10->11 upgrade, as I recall.

Maybe from Windows 3 to 95/98, but I remember (perhaps incorrectly) that moving to 95/98 and/or 7 was pretty stock experience.