I've been working on a large model in Blender 2.7, and I split it into layers to manage it better. Now I've updated to 2.83, and I've learnt about layers being replaced by collections. However, when I open my file in 2.83, I get this in the Outliner:
Even though all collections have the open eye, only the first one is visible, and the View submen only shows the first one:
Is this something related to my file being migrated to 2.83? How do I get all my objects back again?

