I just spent 4 hours with another engineer trying to figure out why our builds weren't producing the same results.

Turns out I had html5lib "0.9999999" and he had "0.999999999" which was nearly impossible to spot on the pip list readout. >.<

http://semver.org/#why-use-semantic-versioning

I'm going to guess that you'll say html5lib isn't ready for production so your versioning scheme is appropriate, but I'm still filing this bug because I'm steamed about losing so much development time. :/