The only available vBulletin importer that is in the member area is for vBulletin v3.8.x, which was released on Oct 26, 2009; nothing newer is available. Additionally, this importer was released along side UBB.threads v7.5.4.
Personally, I have not done any testing of the vBulletin importer with any current build of either product; I'd advise any testing on importing data with an old importer to be done with the version of UBB.threads that is closest to the release date of the importer.
