RubyGems User Guide | RubyGems Manuals

A versioning policy is merely a set of simple rules governing how version numbers are allocated. It can be very simple (e.g. the version number is a single number starting with 1 and incremented for each successive version), or it can be really strange (Knuth’s[#knuth] TeX project had version numbers: 3, 3.1, 3.14, 3.141, 3.1415; each successive version added another digit to PI). Because RubyGems

[youpy]

バージョン番号(major#.minor#.build#) 実装の変更(インターフェースに変更なし)=>build#++ インターフェースの変更(後方互換性あり)=>minor#++ インターフェースの変更(後方互換性なし)=> major#++