[falcolas]

> how much compatibility would it really break

Probably only a few applications; but that's still too many.

And backwards compatibility does matter. A change here means that some few dozen developers have to now troubleshoot a previously-stable application which now fails silently in odd corner cases.

[nytgop77]

then create new type. time2 or datetime13 with improved behaviour and say in docs to prefer newer unless your specicaly know that you need old behaviour.