Finally my xperia x compact got the oreo update an hour ago. I was waiting for it since it should enable inband ringtones.
I found the option to enable them in the developer options.
But unfortunately the switch isn't saved.
I enable the setting, return to the previous menu, choose developer options again and find the switch is turned off again. (and still beep, beep.... ).
Other settings in the developer options are kept as expected ... (e.g. I switched on and off the Max volume setting just above).
Any ideas?
