How did you book this? If you booked directly with one of the airlines then it is likely that this really is one itinerary. If you booked with an online agent it is entirely possible that they cobbled something together and that it's really two itineraries. You need to make absolutely sure it really is one itinerary as far as the airlines are concerned - if it isn't then your connection is not protected, and if you miss it you're on your own and you'll have to buy a new ticket, at full fare - or give up on the idea of flying to Hanover and hop on a train instead, which is probably what I would have done in the first place.

I would I'd say that your chances of making it, with a terminal change and having to go through Immigration, are probably only about 50:50 - the slightest delay and you'll miss it.