The new firmware is now available update for Samsung Galaxy Note2. This update not come with any new features and only improve the phone system performance. This firmware version is 7100XXUEML3 and only for Galaxy Note2 N7100 (international version).
You can go to setting >software update to check for update your phone to this latest firmware. If your phone is running custom software or running original rooted firmware then you cant check the firmware update on your phone. You need to download the stock firmware and manually flash into your phone via odin. Please make sure that your phone model is compatible to this firmware!
Download Android 4.3 N7100XXUEML3 Firmware for Galaxy Note2: Link
Note: Manual flash Android firmware to galaxy Note 2 via Odin will void the phone warranty. So, take it on your own risk.