5Ghz network on Arris Router no longer available

Starting about 7:30am EDT on May 26, 2025, my ARRIS SBG6700-AC stopped showing the 5Ghz network that had been working for years.

I had previously set up both 2.4Ghz and 5Ghz networks, and I could now only see the 2.4Ghz one.  AND, the firmware on the device no longer allows me to set up both networks.

What has happened?  Xfinity controls the firmware on these devices now.