. They have the arduino pinout.The R1 and R3 have A0 buttom left .The R2 has A0 + SDA, SCL and GPIo's to Board pins are screwy, so I'd say stay with R1/R3..My WEMOS R1/R3 will support 4 relay Catalex shield directly.I am using I2c LCD using 5 volt and DS3231 using 3.3 ...