This update includes quality improvements and security fixes. No new operating system features are being introduced in this update. Key changes include:
- Improved reliability of Internet Explorer 11, Microsoft Edge, Cortana, audio playback, audio playback in Groove Music app, Maps app, Miracast, and Windows Explorer.
- Fixed issue with balloon tip notifications always appearing in the upper left side of the screen.
- Fixed issue that caused VPN to not work properly when switching between different network interfaces (for example, switching between Wi-Fi and cellular).
- Improved Narrators ability to read bulleted lists, hyperlinks, and image information.
- Fixed issue in location that caused navigation apps to lag behind actual location. Improved performance of loading webpages in Internet Explorer 11 when roaming user profiles are used.
- Fixed issue that caused phones to stop ringing from an incoming call, if interrupted by an SMS.
- Fixed issue that caused some phones to be unable to re-add a primary Microsoft account without resetting after upgrading from Windows Phone 8.1.
- Fixed additional issues with Microsoft Edge, Internet Explorer 11, Bluetooth, Cortana, Wi-Fi, Windows Camera app, revised daylight saving time, USB, TPM, Graphics, Group Policy, downloading music or movies purchased through Microsoft Store, Network Diagnostics and Windows Explorer.
- Fixed security issues with Internet Explorer 11, Microsoft Edge, Server Message Block (SMB) Server, Microsoft Graphics Component, Group Policy, DNS Server, Windows Diagnostic Hub, Kernel mode drivers, Microsoft Windows PDF, Windows Structured Query, Adobe Flash Player, JScript and VBScript, and Web Proxy Autodiscovery Protocol (WPAD).
For more info about the security fixes in this update and a complete list of affected files, see KB3163018.