This week, open source jQuery developers announced the first release candidate for jQuery 1.5.
“Barring any major bugs,” jQuery creator John Resig said, “this should be the code that we end up shipping for jQuery 1.5 (which will be happening on January 31st).”
Key new features in jQuery 1.5 “include a complete rewrite of the Ajax module, deferreds, and subclassing,” according to Resig.