Well, head over to settings>about phone>software updates>Tap over check for updates, if it appears like "All updates have already been installed".. or something similar means you can't update your device of KitKat as your vendor haven't released the update for you. What I think is Note 2 devices aren't over the updating list by samsung and that may be the reason why ... anyway I don't think that you are going to get and update by your vendor.So better option would be moving forward with rooting your device and trying some custom ROM out, you can step ahead with CyanogenMod.