What's the new MB dealer oil?

[Will_w202]

I had the dealer do my oil and filter since it was in for shocks, and it was time. This is the first shop-performed oil change done since the car ran out of warranty 40k ago. I thought I would have them put in 0w40 M1 for the winter months. I've been using 15w50 extended life.

My rep said they no longer use that, and went to an MB-branded 5w40. I assume it's M1......anybody know? Doc? I know you do!