I saw many questions about returning back to official device status and receveing OTA updates after device was rooted with or without a different custom rom.
All you need is Odin3_v3.09 and your official ROM witch you can download it from here http://www.sammobile.com/firmwares/1/
1. Shut down your device, and turn it on in download mode (VOL DOWN + HOME + POWER) than enter download mode (VOL UP)
2. Install Samsung drivers for your model.. search google
3. Open Odin connect USB cabble wait for connection COM to come blue or yellow
4. Load as PDA / AP your file extracted *.tar.md5, be sure that you didn't tick other than Auto Reboot and F. Reset Time
5. Hit START ! (don't touch your device, don't chuing your cabble ..don't move it .. just do nothing !!!)
6. When you see a green message FINISH in up left corner you can unplug the cabble and just wait for device to boot
Now you are UNROOT-ed .. your KNOX is still 0x1..and that means you cannot use Knox if you try to install / run it will say " Your device is not authorize to use Knox".. BUT you can download OTA updates and everything seems to get back to how it was .. Device status become also Official
You can Re- Root anytime you want..
Good luck guys