Umi max bluetooth problem after android 7

Kats-7

I have recently updated my Umi Max and now it is using the Android 7. But a problem arose. When I connect it with my Ford car or my headset through bluetooth and somebody calls me, the SIM signal is dropped until there is no signal and so, the call is canceled. So, I cannot speak through bluetooth. The signal of sim is missed immediately. What can I do? I restarted it but...nothing!

Gegerap86

Wait for a fix on the bluetooth or reinstall android 6.0 because there is a bluethooth bug on the version 7.0 of the umi max I hope that umi has predicted the fix i wait if you want reinstalle version 6 i can tell you the Manipulation has to do but you to reinstall all programs attention greeting

PVK

I have problem with my Bluetooth - it is paired with the phone, but I can only listen to music and don't have access to the phone, I can not receive calls.  I tried to check the box named "Phone audio", but I can - it want check! Any help?

AZJMS

Same with Umi plus.
Umi do something.

amonapophis

After much consideration I decided going back to Android 6. Now Bluetooth became stable and fast. So this is the only way of fixing it.