I just got a updated to blender 2.8 and my objects that were in hidden layers are gone now, the collection layer tells me that they are in the scene but I cant unhide them also the collection is grayed out as well.
If it's been hidden in the viewport in 2.79 you can make it visible in 2.8 by going to the Outliner.
Click on the filter icon and under Restriction toggles select Disable in Viewport (screen icon).
You can now set the collection back to being visible by clicking on the screen icon behind the collection.
I also have such a problem, but I solved it. Here is what you need to do: Right-click on “Collection 1” -> “Visibility” -> “Enable in viewport”. That's it, now hidden layers will become active.
P.S. I also noticed that the files saved in the new version of the program, unfortunately, do not open in older versions of the program. The blender just closes when you try to open new files. No version compatibility, this is sad.
It seems like I was typing a message for too long, they got ahead of me :)