Updating Raspberry Pi

My image is from the AD2Pi stock firmware and the only update has been to the AD webapp. I am wondering if I can do an rpi-update and apt-get dist-upgrade on my Pi that has the AD2Pi? If yes, what are the steps to follow without loosing my settings?
The current distribution of raspberry pi is at 4.1.19+ #858 while my AD2Pi RPi is at 3.18.11+ #781
The current distribution of raspberry pi is at 4.1.19+ #858 while my AD2Pi RPi is at 3.18.11+ #781