EMA C++ RDM Usage Guide : 5 Dictionary Domain : 5.7 Special Semantics : 5.7.2 Version Information : 5.7.2.2 Handling Dictionary Version Changes
 
5.7.2.2 Handling Dictionary Version Changes
To keep consumers informed of changes, LSEG recommends that dictionary requests be streaming even though updates are not used for this domain.
If the dictionary’s minor version changes, a provider may advertise it via a StatusMsg with a State of OmmState.Open/OmmState.Suspect. The consumer may then reissue its dictionary request to obtain the latest version.
If a dictionary’s major version is changed, the provider should disconnect all consumers to ensure that the consumers’ content and dictionary are entirely resynchronized.