According to my findings, the "new improved" cap has a blue dot inside near the threaded portion. My M8 has no issues.
I haven't got a letter yet. The recall did extend to the late 16's , right?
If you are having an issue, just go to your local dealer and they will give you a new one. If you aren't having an issue, just check and make sure it has a green (or blue) dot on the inside of the cap.
No dot but no letter either. Nor is there a recall listed for the gas cap with the vin. Mine was a very late year '16 if that matters.
Oh my god the new one goes on soooo much easier. Even my dealer was like damn man, how have you been dealing with this. I said I was going to complain as soon as I came in for the 1k service.(I'm just at 920m right now) The new one is butter smooth.