I recently bought a DVI to USB adapter so that I could plug a second monitor into my 2012 MBA. It wasnt until I actually set it up that I learned of all the trouble. I wouldnt say the set up I have now is perfect but it is workable.
I'd hate to upgrade to Yosemite and have everything go to hell though. Is it possible to downgrade if I have problems?
If your on Maverics you should be Ok not upgrading for a while. I used one of those adapter with snow leopard on a mac book up to this spring (upgrading compatability being questionable). It finally became clear that enough software needed a new OS that I got a newer machine.
Mavericks beachballs on a way faster machine more often than it ever did on snow leopard. I miss that os.
I'd hate to upgrade to Yosemite and have everything go to hell though. Is it possible to downgrade if I have problems?