Xrefs enable you to begin with a drawing that contains walls and other spatial elements that you need, such as a floor plan, reflected ceiling plan, or AutoCAD MEP 2022 toolset building model.
If you attach or overlay an xref created in a previous version of the software, the file format of the xref is not updated to the current version (which would make the xref incompatible with the version in which it was created). The exception to this is when the xref contains annotative objects, and the host drawing is configured to automatically add scale representations to annotative objects as the annotation scale changes.