EMA C++ RDM Usage Guide : 5 Dictionary Domain : 5.7 Special Semantics : 5.7.2 Version Information
 
5.7.2 Version Information
The version of a dictionary is normally available in Summary Data in the payload of a RefreshMsg. All available verbosities are expected to include this information. The verbosity DICTIONARY_INFO can be used to request only the version information (as the many fields in dictionaries tend to result in large messages).
This information normally comes in the form of a ASCII containing a dotted-decimal version number, indicating first the major version, followed by the minor version, and possibly followed by a third (informational) micro-version. For example, in the string 1.2.3:
1 is the major version
2 is the minor version
3 is the micro-version