Just two observations that I wondered if they can be fixed:

First one:
Just I updated the new firmware 14th jan, I noticed that during voice calls the sound of the other person on the line goes very quiet for about 15/20 seconds before returning to normal quality? Is this just me or are others experiencing this same problem since the update? It was 100% before I did the update.

Second:
not related to any update, but I would like to know if there is some way of locking the screen so that when I receive a voice call that I have to "swipe" or unlock the phone before I answer it?
For example, twice yesterday when i was receiving a call, I picked the phone out of my pocket only to press the "end" icon by accident. Therefore ending the call without meaning to.

anyone know how to help with the above two scenarios?

Thanks in advance.