Microsoft has posted a list of what has been fixed and what has been improved in the new Windows 10 PC 1511 cumulative update for build 10586.318.
Here's the official change log for the update that's currently rolling out:
- Improved reliability in a number of areas including Cortana, Bluetooth, Shell, Internet Explorer 11, Microsoft Edge, Miracast, and USB.
- Fixed memory leak that occurs when opening a portable document format (PDF) form multiple times.
- Fixed issues with text alignment for right to left languages in Internet Explorer 11 and Microsoft Edge.
- Fixed issue that affected Bluetooth function when a PC resumes from sleep.
- Fixed issue where user accounts weren't locked out after a number of failed sign in attempts.
- Fixed issue with revised daylight saving time.
- Fixed issue that sometimes corrupts CompactFlash cards inserted into a card reader.
- Fixed issue that caused recorded video to be lost when answering an incoming call on some phones.
- Fixed issue that could result in unexpected battery drain while the phone screen is off.
- Fixed additional security issues with kernel mode drivers, remote procedure calls, the Microsoft Graphics Component, Internet Explorer 11, Microsoft Edge, Windows Shell, Windows Journal, Virtual Secure Mode, Schannel, and Jscript.