Seems to be a few critics in here but I think a good usecase for calendar versioning is crypto and security critical libraries. You hear about about WPA3 being

Seems to be a few critics in here but I think a good usecase for calendar versioning is crypto and security critical libraries. You hear about about WPA3 being broken in April 2019. It's obvious your WPA3 18.10 lib is vulnerable, WPA3 19.04 is not. It's a lot simpler to parse and can lead to less mistakes.