Is it possible to use Arduino D4 to control Relay 1?

It's easy to make it just by removing the jumper on the board and then connect the pin of Relay1 to any Digital pin you need.

https://raw.githubusercontent.com/DFRobot/DFRobotMediaWikiImage/master/Image/Relay_Shield_DFR0144_sch_for_xbee.png