Да. Обновить можно.
QUOTE
ou can upgrade to the latest version of vBulletin 3 from the following vBulletin versions:
*Any previous version of vBulletin 3, from version 3.0.0 Beta 3 to the current version.
*Any version of vBulletin 2 from version 2.2.9 and newer. If your vBulletin version is older than 2.2.9, you will need to upgrade to at least vBulletin 2.2.9 before you can upgrade to vBulletin 3.
Мануал можно посмотреть тут: