App either hangs with a white screen (if installed from fresh) or shows a error message (if installed over an older 6.X app) "Bootstrap error page: Your app specifies authentication at startup, but there are no credentials. Did you run [[SalesforceSDKManager sharedManager] launch]? Error context: AppLoading"
Should use biometric authentication when passcode policy is enabled in the connected app.
if started from a sample app created with forceios please ensure that you add the required entry in the apps plist for FaceId (NSFaceIDUsageDescription) and try. If upgrading your app from 6.x to 7.x there will be a few changes required for launching your app. Please get a template from forcehybrid and proceed.
<dict>
<key>NSFaceIDUsageDescription</key>
<string>"Unlock the app"</string>
</dict>
This feature is linked with the usage of pin code in your connected app. So please make sure that the connected app in salesforce is setup with that policy.