Updating my V2 to 126.96.36.199 was normal. Worked as expected.
Updating my Pan-cam to 188.8.131.52 was problematic. On the first attempt, the update process started as usual. The progress bar progressed to about 30%. The camera was heard going through the reboot cycle. But the update screen vanished and I was back looking at the Detail page, showing the previous version was still installed. No error message was displayed to indicate that the update had failed. For good measure, I restarted the camera. No change - it still had the previous version. I went through the update procedure a second time, and this time it worked.