Found on [this](https://www.reddit.com/r/Monitors/comments/167dphy/force_enabling_auto_hdr_on_unsupported_games) Reddit post.
- Add a registry key with any name to HKEY_CURRENT_USER\SOFTWARE\Microsoft\Direct3D, with the string value being the name of the EXE - Add/set the key D3DBehaviors to BufferUpgradeOverride=1 or BufferUpgradeOverride=1;BufferUpgradeEnable10Bit=1