Jelly Bean 4.2.1 leaks for OG Samsung GALAXY Note
It should be noted that unlike the N7000XXLSA leak revealed by Xda, which came from a dump of a person's device, a source for SamMobile says that the version of the update that we are discussing came right from Samsung's servers. All you need to do is flash the update with Odin and you're updated. Again, the issue with the S-Pen would concern us a little and you might want to wait for the official OTA update which is supposed to arrive late this year or early next year.
Among the cool changes included with the update are Project Butter (or is it "I can't believe it's not Project Butter?"), Multiwindows, customized notification panel, Pop-up Play, Smart Rotation and Google Now.
source: SamMobile via AndroidCentral