This read-create Unsigned32 (0-100) specifies the version number of a tone plan for a given country, since one country may have several tone plan variants sharing the same country code, and the combination of country code and this version must be unique. Administrators use it to manage multiple revisions or regional variants of a country's tone plan side by side. For example, if a country's official call-progress tones are updated, an admin can add a new version entry rather than overwriting the existing tone plan used by other interfaces.