The Apple document “Information Property List Key Reference” says that CFBundleShortVersionString represents a release version, whereas CFBundleVersion represents any build, released or not. Also, CFBundleShortVersionString can be localized, though I don’t know why you’d want to, since they say it is supposed to be “a string comprised of three period-separated integers”. For a release build, it would be reasonable to make the two numbers the same. For a development build, you might tack something else on to the CFBundleVersion, maybe another dot and integer.