alt Hacker NewsMaybe the database upgrade from v(N-17) to v(N-16) simply takes a while, and hasn't completed yet? Or the responsible team is looking at it, but it doesn't warrant the whole company to stop shipping?
Being 17 versions behind is an extreme example, but always having everything run the latest version in the repo is impossible, if only because deployments across nodes aren't perfectly synchronised.
This is why you have active/passive setup and you don't run half-deployed code in production. Using API contracts is a weak solution, because eventually you will write a bug. It's simpler to just say "everything is running the same version" and make that happen.