IOS7 appears to have been installed on my Iphone 4. It comes on, apps start but then the "restart screen" appears after 1-30 secs. After another 20-60 secs, the "restart screen" disappears and the app begins where it had left off.
Just to be clear, by "restart screen" I mean a black background with centered white apple and a progress bar beneath the apple. The progress bar lights up to maybe 1-3% but never any further (and sometimes less) no matter how long it remains in this state.