I was able to register at the link provided above (without having received the invitation). I got an e-mail confirmation after registration: " Besten Dank für Ihre Teilnahme an der Promotion "Keep Status". Falls Sie Fragen zur Promotion haben, wenden Sie sich bitte an das Miles & More Service Team, Telefon +41 (0)848 85 6000." Let's what will happen.
Thanks for posting this!