Microsoft has begun rolling out an over-the-air update to all Windows 10 Mobile devices with the version number of 10586.545. This is not the much-anticipated Anniversary Update, which is still due for release in the coming weeks.
Again, this update is meant to fix some bugs in Windows 10 Mobile. As we previously reported, the big Anniversary Update for the mobile OS is stil due for release sometime "in the coming weeks" but does not yet have a firm date.
Thanks to Hardik and witterholt for the tips!