https://discuss.python.org/t/requires-python-and-pre-release-python-versions/62959/46 https://discuss.python.org/t/requires-python-upper-limits/12663/84 - Support `>=` - Error/warn if specified more than once? - No upper bound because you can't know if it will be a problem - Support `!=` - Can be specified multiple times - Was useful in 2->3 transition - Ignore release level - Treats the requirement as a hard minimum, not a guaranteed minimum - Can't know which release will meet the requirement the project has, so either have to exclude everything (which makes testing hard), or include it (which assumes users of a pre-release know what they are doing)