This seems like a nice to have feature, so I wanted to forward it from rpm.org's trac (currently read-only):
It would be nice when a special handling of '~' would be introduced to mark "negative" version tokens. E.g. so that
| foo-1.0~beta < foo-1.0
holds. This would simplify complicated rulesets which deal with such naming schemes by abusing %release for it.
This package has changed ownership in the Fedora Package Database. Reassigning to the new owner of this component.
Support for tilde in version/release got added in rpm-4.10.0-beta1, currently in rawhide. It cannot be (yet) used in Fedora packages though, as the build infrastructure runs on older rpm versions which dont know about it and cannot install packages with tilde in version/release.