In order to update your D200/ S800/ S900 card terminal you have to be close to it and the terminal needs to be connected to the network. For the 2 portable models (D200, S900) we advise that they are connected to your WIFI network during the update.
Press the red key (X) and enter the terminal’s Menu.
Use the arrow down button to scroll down until you reach the System menu option. Select it with the green key (Enter).
Use the arrow down button to scroll down until you reach the System update menu option. Select it with the green key (Enter).
Wait until the terminal completes the update.