From 2016 to 2018, I had T-Mobile cell service while living in Boxborough, MA using an iPhone 6S. Whenever I traveled into Harvard, I lost service. There were several areas in central MA where I got no service.

I don’t live in that area anymore, but since 2021 when I finally got a 5G-capable phone (iPhone 12), I’ve always gotten a signal along and inside 495. If you have a 5G-capable phone you should be good to go.