Calabash tries very hard to comply with Semantic Versioning [1] rules.
However, the semantic versioning spec is incompatible with RubyGem's patterns for pre-release gems.
"But returning to the practical: No release version of SemVer is compatible with Rubygems." - David Kellum [2]
Calabash version numbers will be in this form:
<major>.<minor>.<patch>[.pre<N>]