That should be an easy one to sort…Ring’s answer seems to be way-off! Was that answer from Rings call center in the Philipines?
I’m still using a couple original stick-up cams with a Micro usb solar panel and a couple of Gen 2 with the original panels.
One panel failed…and a new barrel connector version is enroute…so I will be following your post…Micro Solar USB versions are still available…but I would just chop the cable and wire on a new micro USB 
if I had to…