A test Android 4.3 firmware for the Samsung Galaxy Note II (N7100) has been leaked on the boards of Vietnamese Tinhte by forum member HappyKing. The early build comes after only a week or so ago Samsung started testing the latest iteration of the Google platform on the Galaxy Note II.
If you're familiar with the crowd over at the XDA forum boards at all, then you can probably guess that the firmware is already up and ready for downloads from several mirrors. Keep in mind that while the firmware has been so far reported stable, this is a test version so thread carefully and go through the usual back-up checks if you're planning on doing some flashing.
So far, the new update has brought the Note II's UI up to speed with its successor, the Note 3. A lot of features, among which Samsung Knox and Samsung Wallet have also been added, and we can only guess that more are to come. What's probably most important, though, is that some users have reported that performance has increased, though we can't confirm this right now.
Thanks for the screenshots, Parth!