Here is DJI's official response:
Here is the official reply HQ drafted:
1、IOS app download:
Thank you very much for your support and patience. We are extremely sorry to say that the DJI-Pilot App has been delayed for iOS devices. DJI is working hard on this to push the approval process through with Apple and will keep you informed of any of our progress.
Currently we provide Android App for you to use. The recommended devices are as below: Samsung S4, S5, Note 3, P900 tablet, Sony Z3 EXPERIA, Google Nexus 7 II, Mi 3, Nubia Z7 mini.
Thank you, and sorry again about the delay.
2、Non GPS mode issue:
Actually it is not GPS problem. DJI adds more critical standard to compass checking in latest firmware, it will switch to NON-GPS mode when compass data is abnormal during flight. You can judge from the LED of aircraft, RED and YELLOW. For GPS signal, trust the GPS icon in APP.
3. IMU bug:
The issue is believed to be caused by the accelerometer got shocked during transportation. And once powered on, it will give false data, thus the craft will drift to one side rapidly. The new FW .16 should fixed this issue.
4. Prop shooting:
It can be caused by different reasons: un-tightened props, sand in motor, strong wind and etc. DJI is releasing new accessories to lock the prop to prevent the prop from losing. Meanwhile, please make sure the prop are securely tightened before flight. And minimize the flight if possible.