4 years ago(?) they stopped distribution of german version and there was always a notice on
http://www.vbulletin-germany.com to transfer your license to vbulletin.com.
I don't know if there is help possible on
https://forum.vbdev.de/ (the former forum of
http://www.vbulletin-germany.com). But at the end you have to ask on vbulletin.com (forum) if there is a late license transfer possible and how.