Microsoft last pushed Windows 10 Build 10586.240 to Insiders in Release Preview Ring and you can read the full official changelog by clicking here. Now it seems the Build 10586.240 is available in Microsoft’s production servers and can be downloaded as Cumulative update KB3157621 using the official Microsoft update catalogue links. Click on the below official links to download it for both X64 and X86 devices.
The last Build released for Windows 10 version 1511 is Build 10586.218 and as mentioned above the cumulative update takes it to 10586.240.
