Phone gets connected but the sound is not coming out of car speakers but phone speakers.

Bluetooth Connection Issue: Sudden drop connection between the App and the external BLE device PLATFORM AND VERSION iOS 14.7.1 and above (15.0 beta) The iOS App will connect to an external BLE device with the help of the CoreBluetooth framework. DESCRIPTION OF PROBLEM In iOS 14.7.1 and above (iOS 15.0 beta), observe a sudden drop in the connection between the App and the external BLE device during the firmware upgrade process via Over the Air (file size 500 KB, file type ".bin"). The same App is working fine with iOS 14.6 and earlier versions of iOS. It observes that MTU size is also different in iOS 14.4 and iOS 14.7. When disconnection happened CoreBluetooth -> centralManager: didDisconnectPeripheral delegate method called. The total time required to update BLE firmware is 2 minutes, but approx after a 1-minute or 30 seconds connection is dropping between the App and the BLE device. Do I miss anything that causing a sudden drop of BLE connection, specifically in iOS version 14.7 and above? STEPS TO REPRODUCE Connect the iOS App with an external Bluetooth device and start writing/sending the data from the phone to the BLE device continuously in BLE specified UUID. After some time approx 30 seconds or 1-minute observe a sudden drop in the connection between the App and the BLE device.

Bluetooth Connection Issue: In iOS 14.7.1 and above (iOS 15.0 beta), observe a sudden drop in the connection between the App and the external BLE device during the firmware upgrade process via Over the Air (file size 500 KB, file type ".bin"). The same App is working fine with iOS 14.6 and earlier versions of iOS. It observes that MTU size is also different in iOS 14.4 and iOS 14.7. When disconnection happened CoreBluetooth -> centralManager: didDisconnectPeripheral delegate method called. The total time required to update BLE firmware is 2 minutes, but approx after a 1-minute or 30 seconds connection is dropping between the App and the BLE device. Do I miss anything that causing a sudden drop of BLE connection, specifically in iOS version 14.7 and above?

While writing data in BLE device connection loss happened in between BLE device and application (file size is 459 KB, the file type is .bin). It's happened particularly in iOS 14.7.1 and above. iOS 14.6 and before iOS, it will work fine. It observes that MTU size is also different in iOS 14.4 and iOS 14.7. When disconnection happened CoreBluetooth -> centralManager: didDisconnectPeripheral delegate method call. Divide bin file data into 1024 chunk sizes and write data into BLE device as per receive MTU size (MTU - 3) Is any string that needs to add for iOS 14.7 and above or what should I needs to check.