A new build, Windows 10 Mobile 10586.63, has been released to the fast ring. The update fixes certain issues and adds some new features according to Reddit user 'jenmsft', who claims to be a Microsoft employee. She states that the new build makes the platform more reliable, and contains battery and performance improvements. It gives users the ability to type on a Polish QWERTY in Outlook Mail. It also allows a Windows 10 Mobile phone to disseminate turn-by-turn directions in a car, over Bluetooth.
After installing the new build, using the Windows Hello iris recognition feature will eat up less battery life than before. The update allows the Quick Action settings page to become more reliable, and you will notice improvements when using the Microsoft Band with Cortana.
According to Microsoft VP Gabriel Aul, the update will be evaluated over the next few days as fast ring subscribers get to use it. If all goes well, Windows 10 Mobile build 10586.63 will be pushed out soon to those in the slow ring.
source: Reddit via WindowsCentral