Update: Build 10586.456 is also available for Windows Insiders in the Release Preview ring for PCs:
Windows Insiders in the Release Preview ring: Make sure you check out the new 10586.456 update! Available for both PC and Mobile!
— Windows Insider (@windowsinsider) June 29, 2016
Microsoft has been testing Windows 10 Mobile Build 10586.456 for a little while now. The company today released the build to Windows Insiders in the Release Preview for Mobile devices. If you are in the Release Preview ring, you will be able to download the build by heading over to the Update & Security section in the Settings app. As per usual, as this is a cumulative update, the build does not include any new features and it probably includes several bug fixes which are always nice to see.
At this moment, there isn’t any changelog available for the build just yet – however, Microsoft will likely provide a changelog within the next few hours. Once the changelog is available, we will update this article with more information.