Answer
What you are experiencing is due to how iOS handles Bluetooth Low Energy (BLE) service discovery and GATT service caching.
During the intermediate reboot phase of a firmware update, the RS26x briefly operates in a minimal state where it only exposes the firmware update service (SMP) and does not advertise the application communication service (NUS). iOS detects this change and automatically caches the reduced list of services to save power. When you reconnect after the update completes, iOS continues to rely on that cached list and assumes the device only supports firmware updates—failing to discover the NUS service needed to view and edit sensor settings. This caching behavior is unique to iOS, which is why Android devices are unaffected.
To clear the cached GATT services on your iOS device and restore full configuration functionality, please perform the following steps:
Force close the app: Swipe up from the bottom of your screen to open the App Switcher, then swipe up on the Xbit Mobile app to close it completely.
Open iOS Bluetooth Settings: Open your device's Settings app and select Bluetooth. (Note: Toggling Bluetooth via the iOS Control Center shortcut will not clear the cache).
Toggle Bluetooth: Turn the Bluetooth switch OFF, wait 5 seconds, and turn it back ON.
Reconnect: Re-open Xbit Mobile and connect to your RS26x sensor.
Toggling Bluetooth directly within the iOS Settings app forces the operating system to clear its saved service cache and rediscover all active services on the RS26x.
If the above steps do not correct the issue, please email our technical support team (support@ezurio.com) for additional assistance.