Review on HiLetgo PCF8574 PCF8574T IO Expansion Board I/O Expander I2C Evaluation Development Module (2pcs) by Adam Clemons

The address pins (A0, A1 and A2) on BOTH the boards I received were grounded on the PCB. The top one is where VCC is and the next 2 columns were shorted on the PCB between ground and AO, ground and A1, and ground and A2. This prevents you from removing the bottom from the pin to pull it up. It also means that if you try to pull an address pin high, you're shorting VCC to ground. To change the address you will need to unsolder the address pins you wish to remove from the board.