they said that the very last show will be in an stadium. in germeny there are 2 1/2 stadiums that have a roof. there is the arena in schlake of football clun schalke04 with the cap. of 60.000people and there is the arena in Düsseldorf with 50.000cap. the third is in halle a tennis stadium with arround 15000 seats.
the stadium in hannover itself has no roof, and to be honest open air concerts in germany before end april/mai doesn't make sense, because at nights it is still to cold outside when se sun is gone. an alternative would be other countries more south like spain or the south of france ... let's wait and see