To convert this files you may need to have 4.33 (uses v73), or even both 4.33 and 4.34 (uses v100) if converting directly from 4.33 to 4.35 (uses v103) gives failure because converting needs references to the database of each version and I am unsure if you can directly jump from v73 to v103 (Although I would try that first If I were you)
You are more than right on these, bro, I guess…
the last time I attempted to do that kind of conversion was a total failure, at least.
So this is more probably the reason, and the db is the key, as usual.
With best regards.