In order for us to keep the cost of the Prop-1 so low, we are forced to do high-volume runs with manufacturing partners. These partners will not manufacture using components that have gone obsolete. Such is the case of the DIP (socketed) version of the ULN2803, forcing us to update the board to the SMD (surface mount) version.
We often need to disconnect P7 or P6 from the ULN input circuitry, and with the previous versions we could change to the ULN2003 or clip the pins. Pin clipping is still possible, but no user repairable for a new configuration.
There are new jumpers that allow for the Prop-1 to be configured for various setups. Please see the attached document.