Just yesterday, Microsoft released Windows 10 build 10586.338 for Release Preview ring insiders but there was no change log. Here is the change log for this build.
- Improved reliability in numerous areas including Internet Explorer 11, Microsoft Edge, Cortana, audio playback, Groove music playback, the Maps app, Miracast and Windows Explorer.
- Fixed an issue that was causing balloon tip notifications to always appear on the upper left side of the screen.
- Fixed an issue that caused VPN to not work properly when switching between different network interfaces (Wi-Fi, cellular etc.).
- Improved Narrator's ability to read bulleted lists, hyperlinks, and image information.
- Fixed an issue in location that affected navigation apps to lag behind user's actual location.
- Improved performance of loading webpages in Internet Explorer 11 when roaming user profiles are used.
- Fixed an issue on Mobile causing the phone to stop ringing from an incoming call, if interrupted by an SMS.
- Fixed an issue on Mobile that affected some users to lose their contacts, messages, and appointments 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 the Windows Store, Network Diagnostics and Windows Explorer.
Users who are on Release Preview ring should already get Windows 10 build 10586.338 installed through Windows Update. Source: Jen Gentleman.