If you are on stock firmware, Samsung no longer pushes OTA updates for the Note II. The last official update was Android 4.4.2 (KitKat) with build date around 2015.
Many Note II owners have experimented with Custom ROMs like LineageOS or CyanogenMod to get newer versions of Android. However, if you miss the stability of the original TouchWiz interface or need features specific to the stock Samsung experience (like specific S-Pen functionality), you will need the stock firmware to return to the "out-of-the-box" state. sm-n7100 firmware
Yes, but you will lose your original carrier settings. To change CSC, flash a multi-CSC firmware package and then dial *#272*[YOUR IMEI]# to select a new region. This will factory reset your device. If you are on stock firmware, Samsung no
Generally more stable than 14, providing a great balance for daily use. Classic "Ditto" ROMs: Older fan favorites like Ditto Note 3 (DN3) However, if you miss the stability of the
Original S-Pen features (Air View, Multi Window) and total reliability. Where to find it: Authorized archives like host the original build files for various regions. Custom ROMs (The Modern Route) Android 14 (LineageOS 21):
This is the original software released by Samsung. It is stable, safe, and comes with the classic Samsung TouchWiz interface.