I'm in Boston and it wasn't installed on my phone (exposure notifications have always been off AFAIK). I'm on old iphone 5s, not sure if that makes a differenc

I'm in Boston and it wasn't installed on my phone (exposure notifications have always been off AFAIK). I'm on old iphone 5s, not sure if that makes a difference or maybe just specific areas? According to this, https://thesomervillenewsweekly.blog/2021/04/05/massnotify-app-alerts-users-of-possible-covid-19-exposure/ https://thesomervillenewsweekly.blog/2021/04/05/massnotify-a..., different cities were piloting at different times, although it all seems opt in.