It seems like a *really* unhealthy idea to me to silently change numerical values. Despite the extensive communication, the vast majority of your users will not be aware of what's happening and run the risk of silently getting invalid results. I can't think of any important package in the SciPy/PyData ecosystem that has ever done what you're proposing after becoming popular. I would recommend to change the package name or name of the main namespace, to make sure people see an exception and become aware of the problem when they upgrade.