Microsoft has posted a list of what has been fixed and what has been improved in the new Windows 10 Mobile cumulative update for build 10586.318.

lumia 950

The full change log was posted on Microsoft's support forum:

  • Reliability, performance and stability improvements.
  • Fix for a problem that could result in unexpected battery drain while the phone screen is off.
  • Improvements to the update system to prevent phones getting into a state where attempting to take an update may lead to errors 0x800f081f or 0x80070570.
  • Fix for a problem that caused some phones to finish the initial setup wizard with an incomplete set of app tiles on the Start screen.
  • Improvements to the reliability of USB-C connections.
  • Improvements to Cortana, including a fix for a problem where music playback would not resume after dismissing an incoming text, and a problem with Quiet Hours not setting automatic rules for every day.
  • Fix for a problem that could result in the phone to hang or restart when visiting certain web pages in Microsoft Edge.
  • Fix for a problem that caused recorded video to be lost when answering an incoming call on some phones.
  • Improvements for reliability of internet connection sharing (ICS) and tethering.
  • Fix for a problem that caused the navigation bar to overlay and hide part of the screen for some apps on certain phones.

This update is for smartphones that shipped with Windows 10 Mobile pre-installed such as the Lumia 950, Lumia 950 XL and the Lumia 650.