I had the strangest experience, after the update...
I re-booted the phone, a day after the update. At the time of the re-boot, the phone was charged to 100 percent. After the phone came up to normal, I got the warning that the battery was down to 5 percent, and to plug it into the charger immediately, along with the red flashing warning light. I couldn't imagine how the battery could discharge in just a few minutes. But, after hours on the charger, the charge was still 5 percent.
I got suspicious, and did a full shutdown, but while it was still on the charger. Immediately, the battery monitor booted up and told me the battery was 100 percent, and with the green light.
I let it sit for a while, then re-booted. Sure enough, after the phone came up to normal, the battery read 100 percent, and with the solid green light.
Obviously, the entire episode was some sort of strange false alarm, but what caused it is a mystery to me!