I got those spring loaded pins to reprogram any older hot start relays. They work better than I expected. I reprogrammed 10 older inventory and only had to do one of them twice. The pins are soldered on a blank board to hold the 5 pins spaced correctly. Then I hold that setup on the exposed solder filled holes and hit the program button. The hot start relay is the only relay with the programming pads on the bottom. You can't fit that on the other relays.

I'm marking the units as "C2" to show you it will delay 2 seconds rather than one second if you jumper pads 3 to 4 of those programming pads. Leaving the jumper off makes it delay one second. Note the square pad is #1 so count from that.

I still have a lot of REV C boards but if I ever use them up, a new board will have separate solder pads for the jumper. I don't have any improvements planned for new boards other then replacing the TO-220 MOSFET with a surface mount component. If I had a major improvement I would scrap the boards and get new ones. That same reasoning goes for all my products.