Audio 20 - Bluetooth update possible?

[Herlax]

I have MB W211 E 2008. The car has an AUDIO 20 player. The car's Bluetooth connects normally to my new Motorola Edge 40 Neo Android (V14) phone (hands-free). I can hear the other party's voice well in phone calls, but the other party can hear my voice very poorly. So poorly that nothing comes of the call. My previous phone (2017 Huawei P20 Pro) worked flawlessly. I tested my new phone with the handsfree of 2019 MB C 250 Cdi. Calls were heard flawlessly in both directions. It is obviously so that the old Bluetooth software of my car's (2008) audio system is causing the trouble.

Can the Bluetooth software of my W211 Audio 20 be updated to a newer version? Any other solution to consider?