Update (2017-09-20): a hot-fix for 3.1.1 has been released that resolves this issue.
There is a known issue in IceLink 3.1.1 that causes a crash when running in a 32-bit process on iOS. This will affect 32-bit iOS devices, specifically the iPhone 4S, 5, and 5c, as well as newer 64-bit iOS devices if the application is run as a 32-bit process.
This issue has been fixed for 3.1.2, due out October 4. This is also being evaluated for a 3.1.1 hot-fix in the interim.