We are aware that there are a few issues with the settings menu and the MIDI assignment page on iOS11, on BIAS FX.
A new update will be released soon on AppStore especially for these two major errors for iOS 11 users.
We are sorry if any inconvenience caused. Please stay tuned for the coming update.
The version 1.5.10 of BIAS FX is already available on AppStore. This very version gets the bugs above all fixed.