You can check if inside the JS code you find some "on" instructions and try to replace them with "bind". Many breaks of the code between those two versions are coming from here.Actually, yeah that is lucky.
I wanted to use a jQuery plugin once. Only worked on jQuery 1.7. Broke jQuery 1.4. Had to find some other plugin which was a shame. Hopefully a future version of XenForo will be compatible with newer jQuery.
They had the 'live' (which for me didn't work well on iE) and the 'bind', may be they found a cross browser solution with this "on" command. I haven't tried yet this command (because of Xenforo ^^), but this plugin is great and easy to use.Yeah good call.
I think I fixed one plugin once by doing this but it was still all kinds of broken.
I'm really surprised they didn't maintain compatibility between versions.