As expected, Microsoft released a new major update for Windows 10 versions 10240 and 1511.
KB3156421 is a patch that, according to those from Microsoft, comes with improvements to Windows 10 performance,solutions to several security and vulnerability problems , but also the development and fixing of errors from Cortana, Bluetooth, issues related to USB connections, Internet Explorer 11 and Microsoft Edge. All these features of Windows 10 have been revised in the update KB3156421 for Windows 10.
Specifically, changes were made at the kernel level, changes made drivers which are responsible for connecting the devices via Bluetooth si port USB, la Windows 10.
Cortana, IE11 and Microsoft Edge, in addition to some browser security fixes, changes have been made to reduces RAM consumption, especially when PDF files are opened with IE11 or Edge.
The update is available through the Windows Update Center, and it also includes previous versions/updates, for those who do not have up-to-date systems. Cumulative Windows 10 Update.

This update concerns the versions of Windows 10 1511, and after installing the update, it is necessary to restart the operating system.
And “anniversary update” is expected this summer. This update will bring significant changes to the Windows 10 operating system, both on the performance and security side, as well as on the refinishing of some features already existing in Windows 10.