iOS BLE cannot correctly read the model number.

[Leo Mo]

After updating from SDK V2.1.3 OTA to SDK V2.9.0, iOS cannot correctly read data such as the model number, but Android can read it normally.

Turn off Bluetooth in the system, turn it back on, and it can be read normally after connecting.

[Susheel Nuguru]

Can you also check if you have all the below set?

CONFIG_BT_SETTINGS=y
CONFIG_BT_GATT_SERVICE_CHANGED=y
CONFIG_BT_GATT_CACHING=y
CONFIG_BT_SETTINGS_CCC_STORE_ON_WRITE=y

Make sure that the service changed indication goes from the server to the phone after the OTA is complete.

[Leo Mo]

All these settings have been set to 'y'. It seems that the app (iOS) needs to reacquire the service?