I also have an owned and not expired license - so I have access to the files I would need to upgrade. SO I know I can definitely upgrade my owned (non-expired) forum... My question is: can i upgrade the expired vb installation as well?
I believe you need to have a non-expired license to upgrade it to a version that came out after the license expired. A better place to ask would be vbulletin.com though.
You mean you have two vbulletin license's for two different websites, but one is expired? One license is only good for one site.
If your inactive license is for the site then you can't legally use the other license to upgrade, unless you switch license, leaving the other site, which is using the currently active license, inactive. Just pay $60 for the license.