@Fiat Lux - ASIA 

Yes. I can backup and restore in QB2021.  I can also run verify and rebuild. 

The problem/question relates to advice I keep getting from the QB "call back" techs who are telling me that the problem referenced in the above link (regarding QB2021 not exporting accurately to Excel 2013) requires that I incrementally upgrade the data file through the intermediate releases of QB.

I have had some techs tell me that is required by QBs and others tell me it is not.  And, as indicated, the "trial versions" for these (including a trial version of QB2021 Desktop) are not available?

John Harris