Currently #Debian linux is going through a massive migration project to rely on a 64 bit time rather than a 32 bit time (to avoid #y2k38). Debian has these migrations from time to time. About 10 years ago there was a migration to leap a C++ ABI change. Every time these come up I'm amazed at how well executed they are and by how the core dpkg/apt tools have proven their fundamental over and over again for 30 (!!!!) years. I am so thankful to everyone involved in Debian for such a reliable OS.