Canonical deserves credit for keeping the old-releases server alive and accessible. While Microsoft makes you jump through hoops to find Windows 7, and Apple actively locks out old macOS versions, Ubuntu invites you to explore its entire 20-year history.
md5sum ubuntu-16.04.7-desktop-amd64.iso Compare the output to the list on the server. If it doesn’t match, delete the ISO—it is corrupted or tampered with. Downloading older versions of Ubuntu is like digging through a library's basement stacks. The dust is there, but so are the classics. ubuntu older versions download
LTS releases (04.04, 08.04, 10.04, 12.04, 14.04, 16.04, 18.04, 20.04, 22.04, 24.04) were the "stable ground" of their eras. They received five years of support, meaning their archives are more complete, and their bugs were fixed with surgical precision. If it doesn’t match, delete the ISO—it is