The version number (CFBundleShortVersionString) is a user-visible string that represents the bundle version with a required format of three period-separated integers (0-9).
Each integer provides information about the release in the format [Major].[Minor].[Patch]. For example, in 10.14.1, 10 is the major revision number, 14 is the minor revision number, and 1 is the maintenance release number. This string is used throughout the system to identify the bundle version and should match the version number you enter in App Store Connect.