[Hostboard]

vBulletin 4 in my opinion still remains a very viable platform with the only real limiting factor being a truly responsive/mobile theme.

While I know there are a few new projects out there that fill this need, many have existing themes that they would like to rely on. I would like to recommend if that is the case for you to look at the services of iA1 ( https://www.vb4mobile.com/ ). He was able to transform our modified "stock" theme into a fully mobile compliant theme, passing all of Google's tests. In addition he was able to resolve a few other display issues I had.