The EMS interface board V3 has allowed many people to connect their boiler to a microcontroller.
All connectors on the V3 are on the left side. However, some people want to make a 3D printed enclosure for this board and then it is more convenient to have the UART connector on the other side.
I now made a new revision of this board (V3.1) which has the UART connector on the right side.
It still has the holes on the left side as well, but the connector is only soldered on the right side.
If you need the connector on the left side you can solder one yourself.