This is from the Verizon site: "I currently have iPhone with another carrier. Can I keep my current iPhone when I switch to Verizon?
Yes, if you have iPhone 6 or newer, you'll be able to use it on the Verizon Wireless network."
That's out of date. The 7 posed a new issue when they decided to go with Intel radios that are only compatible with AT&T / T-Mobile services. The Verizon iPhone's have Broadcom chips like the 6S's.