Is it safe to torrent again?

So about 3 weeks ago i received a letter in the mail from my ISP, Charter, telling me i have been caught torrenting and next time my internet will be cut off, i only ever torrented harmless stuff such as older movies that are hard to find, and various tv series. But just yesterday i switched ISP"s to at@t and im just wondering if switching internet service providers changes my IP, and if it should be safe to start torrenting again? and if i was caught, would it be a first strike for them? or does my strike from my old ISP carry over?