Apart from pushing Windows 10 Build 14366 to Insiders in Fast ring and Build 10586.420 to everyone on Windows 10 Version 1511, Microsoft also released KB3163017 (Windows 10 Build 10240.16942) to those on Version 1507 yesterday.
(KB3163017) Windows 10 Build 10240.16942 Changelog:
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, and Windows Explorer.
Improved performance of loading webpages in Internet Explorer 11 when roaming user profiles are used.
Fixed issue with balloon tip notifications always appearing in the upper left side of the screen.
Fixed issue where Shell Launcher stops working when signing in with an administrator account.
Improved support of special character input for some keyboard languages on the sign in screen.
Fixed issue that caused some devices with many processors to hang while rebooting or resuming from sleep.
Fixed additional issues in Microsoft Edge, Internet Explorer 11, Windows Explorer, Peripheral Component Interconnect (PCI), revised daylight saving time, and Microsoft Graphics component.
Fixed additional security issues with Internet Explorer 11, Microsoft Edge, Server Message Block (SMB) Server, Microsoft Graphics Component, Group Policy, Windows Diagnostic Hub, Kernel mode drivers, Microsoft Windows PDF, Windows Structured Query, Adobe Flash Player, and Web Proxy Autodiscovery Protocol (WPAD).