The GroupVersion with DataType VersionTime reflects the time of the last layout change of the content of the NetworkMessages published by the WriterGroup. The VersionTime DataType is defined in OPC 10000-4. The GroupVersion changes when one of the following parameters is modified:

• NetworkMessageContentMask of this WriterGroup;
• Offset of any DataSetWriter in this WriterGroup;
• MinorVersion of the DataSet of any DataSetWriter in this WriterGroup;
• DataSetFieldContentMask of any DataSetWriter in this WriterGroup;
• DataSetMessageContentMask of any DataSetWriter in this WriterGroup;
• DataSetWriterId of any DataSetWriter in this WriterGroup.

The GroupVersion is valid for all NetworkMessages resulting from this WriterGroup.