I2C address three lower bits are set
Shorting column 4 adds 4 to the address
Shorting column 2 adds 2 to the address
Shorting column 1 adds 1 to the address
No column shorted: address 0x20
1 and 4 shorted: address 0x25
I2C pull-up selector
In case many units or long cables are connected additional pull-ups might be required on the I2C lines to compensate for the added capacitance.
Add a short/jumper to connect the 4.7 kohm pull-up to the I2C lines.