We are recommending that everyone update to iOS 12 at this point. iOS 10 had the battery slowdown stuff in it to keep the CPU from crashing because of old batteries and iOS 11 took it out because everyone got made their devices were being slowed down. It appears iOS 12 handles all that better and keeps CPU related crashes from happening. It is device related and is not a software bug. This has been verified by multiple users.
If you don't want to update to iOS 12 you will need to get a new battery installed in the device so it can handle the CPU load of the DJI SDK.