Well, German railway is still using Windows 3.11 https://www.neowin.net/news/age-is-just-a-number-for-30-year-old-windows-311-still-powering-german-high-speed-trains/

At least the nuclear weapons of the US do not require floppy disk anymore since 2019: https://www.defensenews.com/air/2019/10/17/the-us-nuclear-forces-dr-strangelove-era-messaging-system-finally-got-rid-of-its-floppy-disks/