2
i think you should read the news article related to 2.1 1st!
if you note the (unstable) next to where it says download 2.1
2.0.10 is the last stable release, 2.2 hasn't even been made yet!!
2.1.1 is test development release and changes daily and may work 1 day and not the next.. it clearly states not to use it on production websites..