We are trying to shift from using USN_RECORD_V2 to USN_RECORD_V3 to fetch USN records, wanted to know the meaning of MajorVersion in USN_RECORD_V3.
Can I get answers to these questions?
- What is the meaning of the MajorVersion field in USN_RECORD_V3/USN_RECORD_V2?
- Will the MajorVersion field always be 2 for USN_RECORD_V2 and 3 for USN_RECORD_V3?
- How does the MajorVersion value change based on the version of change journal software used, and can changes saved with version 3 be retrieved as version 3 and version 2?
< What is the meaning of the MajorVersion field in USN_RECORD_V3/USN_RECORD_V2?
Same as for all USN records - it tells you which version the record represents, so you know what structure to typecast to. Expect that only one version is present, and expect both v2 and v3 to be found on any system.
Will the MajorVersion field always be 2 for USN_RECORD_V2 and 3 for USN_RECORD_V3?
FWIK, yes. And it would break a lot of things if not 
How does the MajorVersion value change based on the version of change journal software used, and can changes saved with version 3 be retrieved as version 3 and version 2?
AFAIK, only the saved version can be retrieved, because the journal can be massive and conversion takes a lot of time. Yet, software can typecast to the right structure at runtime, without any loss.
Regards, Dejan.