I don't know how long this has been going on, but I had no problem on my 5 with iOS 7.x. When I try to start a post using the app, I can type the text, but everything else locks up...no photos can be added, no scrolling, and the cancel and post buttons don't work either. If I close the app (double click home key, swipe app up) and renter, the text is still there, but still nothing works. I realize I can expect some early adopter issues, but just wanted to report out in case you weren't aware and so others who may encounter the problem know they aren't alone Solidarity!