When installing ConfigMgr 2012 R2 SP1, Windows 8.1 ADK is needed as a prerequisite. You can however upgrade to Windows 10 ADK after installation. Let's have a look. Let's download Windows 10 ADK first on Download kits and tools for Windows 10. At the bottom of the page you will find the Download button. When using ConfigMgr 2016 (Technical Preview), Windows 10 ADK can be used at start already.
Before this can be installed, it's needed to uninstall Windows 8.1 ADK first. After that start adksetup.exe for Windows 10. During setup multiple components must be selected, three of them are the same as in Windows 8.1 ADK. Imaging and Configuration Designer (ICD) is a new one, which is needed to configure Windows 10 settings.
Just select this four items and choose to install them. After installation however, boot images are still on Windows 6.3 (which is Windows 8.1). This because it's needed to update boot images manually. You can choose to change existing boot images or create new ones.
Here are the paths to both boot images:
-x86: C:\Program Files (x86)\Windows Kits\10\Assessment and Deployment Kit\Windows Preinstallation Environment\x86\en-us\winpe.wim
-x64: C:\Program Files (x86)\Windows Kits\10\Assessment and Deployment Kit\Windows Preinstallation Environment\amd64\en-us\winpe.wim
Just copy (and rename) them to the <ConfigMgr folder>\OSD\Boot\i386 and x64 folders. Within the Boot images properties change the Data source location for both files or create new Boot images to the location. Just make sure to select -Distribute Content- and -Deploy this boot image from the PXE-enabled distribution point- (properties) as well. After that both boot images will be on v10.0.10240.16384 which is fine.
Note: As mentioned on TechNet Blogs, don't forget to reboot after ADK installation. Otherwise boot images won't get updated on the DP.
Source: How to switch to Windows 10 ADK on ConfigMgr 2012 R2 SP1
Hope it helps!