hm, the problem is solved until two days, home button working fine. didn't change anything within iOS, all apps kept. such a strange problem, i can tell you!
in another thread here in this forum a user thinks the problem is also hardware- as software-based. on warm, dry days, the problem disappears. when it's muggy the problem appears! in the moment it's warm and dry in my hometown in germany. a couple of days, the day the issue appeared, it was raining and i was standing outside waiting for the bus. perhaps it has something to do with the weather?! can anyone confirm that? i mean, we're already two who recognized that already..