[Pawamoy]

No. When such upper bounds are respected, they contaminate other packages, because you have to add them yourself to be compatible with your dependencies. Then your dependents must add them too, etc. This brings only pain. Python 4 is not even a thing, core developers say there won't ever be a Python 4.h

[akoboldfrying]

> you have to add them yourself to be compatible with your dependencies

This is no more true for version upper bounds than it is for version lower bounds, assuming that package installers ensure all package version constraints are satisfied.

I presume you think version lower bounds should still be honoured?

[zahlman]

The point is that you can know that a lower bound is necessary at the time of publication; an upper bound is either speculative or purely defensive, and has possibly unnecessary consequences for your dependents.