The Redstone update will bring several new features on Windows 10 Mobile devices and these include call audio routing options that will allow users to control where audio is being played when making or receiving phone calls.
Specifically, some leaked screenshots show that Windows 10 Mobile will bring more settings in this regard, so audio during a call can either be controlled automatically or directly sent to a Bluetooth device if any is connected or to the phone speaker.
Furthermore, a second option will allow the operating system to automatically turn on the speaker when the phone is moved away from the ear during a call. This comes in handy in a wide array of scenarios, including when driving or during meetings when more than just one person needs to talk to the caller.
These screenshots published online by MSWin.me come from an unreleased Windows 10 Mobile, but are expected to become available in the coming weeks for users participating in the Windows Insider program and should be part of the final Redstone update expected in the summer.