I purchased (full retail) a Verizon 256GB 7 Plus on October 11 (five days ago.) Upgraded from a 6s Plus. Did the setup/restore, and activation in-store here in Alaska. This is a week 39 phone, and came with 10.0.1 out of the box.
It wasn’t until getting home, setting passwords for various apps, and final setup of the 7 Plus that there was an update. Didn’t think twice, and applied 10.0.2. I really hadn’t used the phone much prior to that and didn’t notice any signal drops or other issues.
I live about 850 feet from the tower. Signal strength is -60 to -65 dBm. I also have a new S7 edge on Verizon on a second line.
Sitting at my desk, with both phones in front of me, I started noticing, after a period, the iPhone dropped to “No Service”. The S7 suffered no loss of signal. I then started paying closer attention, and doing searches of the Internet when I discovered this thread (and, unfortunately, many like it.)
So, my experience is that sitting on a desk, no apps running or open in the background, and the 7 Plus drops the signal. At first it takes a while, but ultimately is every five or so minutes. A reboot does help, buy only temporarily.
I tried all the things mentioned here that seems to have worked for others, but all to no avail. The phone was running 10.0.2, Carrier 25.1, and Modem 1.00.04.
I decided to try the latest 10.1 Beta 3, as some reported success. Shortly after updating to 10.1 Beta 3, Carrier 26.0, and Modem 1.24.00, I suffered the same loss of signal.
I also notice that reception is not as good as the 6s Plus I replaced, which is disappointing. Not sure what I am going to do now, but thank goodness the S7 edge works fine.