PMW3901 Optical Flow Sensor Breakout revisions


We are building an autonomous drone which requires two units of optical flow (PMW3901 Optical Flow Sensor Breakout – Pimoroni) on each drone.
We require that they work on a single SPI bus with a CS for each sensor.
In previous versions (we suspect) of the breakout board it seemed that there was a hardware issue and this was not possible. From our understanding, this is fixed with new models and it is no longer an issue. The attached picture marks the differences between the breakout boards. The left breakout board is what we assume is the newer model, we have succeed in using two of them simultaneously on the same SPI line. What is the difference?