Rendering issues after 4.15 (darkness)

We have migrated on 4.15 version from 4.14 and have very strong visual changes.
4.15 version much more darkness and it affects all the scenes in general.

Screenshot 4.14 version

Screenshot 4.15 version

How to revert changes? Or this is bug?

To me it looks like it’s just less washed out - I know the release notes mentioned some changes to the lighting system. Are you sure you’re not just seeing more accurate colors now?

Note: I understand it might not be what you want - but it seems like you might just need to tweak your colors if you want the exact same look as before. But hey, I’m not an Epic dev, maybe it really is accidental.

I’m blind, Epic Games told what to do in patch note:
You can switch the tonemapper back by adding r.TonemapperFilm=0 to the SystemSettings section of your project’s DefaultEngine.ini. We intend to remove the old tonemapper in a future version of the engine.