The below method tricks the OS into thinking that it is already at the latest version, in effect stopping the update notification from appearing.
I am not responsible for anything you do with your device.
- Device must be rooted
- Download FOTAKill apk
- Put the apk in "/system/app"
- Set proper file permissions (644, or rw-r--r--) for the apk
- Clear "/cache" (e.g. boot into CWM and clear cache)
Check "Settings > About tablet > System updates" and it should show "up to date" now.
Note that after rebooting there may still be a notification to update, after clearing no further notification will appear.
- To re-enable OTA update notification, delete the apk and reboot!