If I am working in a newer version of Revit can I linked an earlier version project?
Yes all Revit will do is each time it will temporarily upgrade for that session. It won’t upgrade the linked file that will remain saved in the version it was created in, until it’s opened and saved in the newer version.
When working with other design team members you should all be working on the same version of the Revit platform.
Note: It’s not best practice to do this and should be avoided and won’t work if you try and link a later version of a model in.