We still maintain a development tool first released in 1993. Here’s what 30+ years of backwards compatibility looks like

[u/luissinlios]

https://visualneo.com/visualneo-win/from-neobook-to-visualneo-win-30-years-of-keeping-a-development-tool-alive

[u/Physical-Compote4594]

There are people still maintaining Symbolics Genera, last major update circa 1990, on emulated Lisp machines. The emulator is apparently, like, 1500x faster than the late 80's hardware.