[ShroudedNight]

One of the stories shared with me while working on OpenJ9 was of a customer that used stack overflows as a scheduling mechanism, and at some point they were compelled to update their JVM to a version that incorporated tail-call optimization, which caused their Rube Goldberg scheduler to stop working (by spinning indefinitely).

I would however argue that the existence of a user relying on behaviour that has explicitly been reserved as subject to change must not preclude development from rendering improvements to products. At some point the consumer needs to be on the hook for relying on a positive externality that they do not have a right to.