Many phones you been rooted but you update it is to contact the Samsung Customer Support to get rid of your phone has been rooted or reset it to factory settings, Which can erase your content and settings.
Samsung phones have a KNOX feature integrated, and it works like an e-fuse that flagged (0x1 from 0x0) if the bootloader has been altered and/or the firmware has been modified resulting to root privileges. This is somewhat irreversible, and this gives clue to Samsung that there has been internal software modifications made to the device which leads then to void your warranty.
Additional information, if your phone is rooted, the firmware status would be 'Custom', and if it is the original firmware, this would be 'Official'. In a perspective, if you have a custom firmware, you cannot update to an official firmware, other than flashing it manually with an official one, so you can use OTA in the future, and this of course will remove your root privileges.