[Esch30]

Speaking of HDR10+, I'm running CoreELEC 9.2.0 stable release on my ODROID N2 into a Denon X8500H receiver which feeds my Sony X900F.  I play uncompressed MKV files.  For titles like Bohemian Rhapsody which feature HDR10+, the color is washed out.  I realize my TV does not support HDR10+ and MKV files do not support Dolby Vision.  Would the latest CoreELEC update help with this and play HDR10+ content as traditional HDR?  Or does this update merely pass through HDR10+ content properly to HDR10+ compatible displays?

Too many variables in the HDMI chain to even make an educated guess.
Simply do a .tar backup of your current CE setup and store that CE .tar backup on your PC.
Then do a -ng nightly .tar update and see what happens.

For HDR10+ to work everything needs to be HDR10+ compatible, including AVR's supporting HDR10+ Video passthrough. Which a LOT of ones do not. 

Thanks for the advice regarding taking a backup first.

I'm not looking to get HDR10+ working correctly since I know my TV doesn't support it.  The closest evidence I can find so far is someone on the CoreELEC forums stating a nightly build from the end of September allowed HDR10 output from an HDR10+ file.  Looks like I'll be doing some testing soon.