1. The projects that have already been built with the base version cannot be upgraded to the open‑world version, correct?
2. Then what are the advantages of the base version over the open‑world version?
Viewing post in MAPGrid - 3D Tilemap/World Builder for Unity comments
1. For the time being, yes, project will not be easily migrated to the Open-World version. I may release an migration tool after the open-world version is complete.
2. The advantage the base package has over the Open-World version is simplicity. Open-World development is vastly more complicated, and unnecessary if you don't need it.