Today is an exciting day for insiders on both sides of the Windows 10 camp. In addition to a new Insider build for Windows 10, Windows 10 Mobile build 10581 has just been released.
There are no new features for this build, as this release seems concerned primarily with bug fixes and overall performance improvements. Here is the list of known issues and fixes. This build fixes the upgrade bugs present in 10536 to 10549, Cortana background draining bugs, as well as several bug fixes and battery life improvements. The Windows team claims performance is dramatically improved and polished, which is a reassuring sign that Windows 10 Mobile is getting ready for RTM release.Further reading: Microsoft, Windows 10 Mobile, windows 10 Mobile build 10581