Moving from 2019.2 to .3 is a lot more difficult than I'd imagine for a point release. But I've worked through most of the issues. The last big one remaining is that every single MeshCollider in the project is reporting this sort of error: This MeshCollider (GameObject: 'Bridge_Support_Sm (11)' Mesh: 'Bridge_Support_Sm') requires the mesh to be marked as readable in order to be usable with the given transform. That's thousands of MeshColliders. I presume this is a bug, as the only remotely relevant mention in the release notes is: - a new Physics.BakeMesh() function to pre-cook meshes for MeshCollider (including off the main thread) (in the context of the PhysX 4.1 Upgrade) In my case this is thousands of meshes. Clearly we don't want to have these in main memory if we don't need too, so read/write is quite sub-optimal. Is this a bug? A new requirement? A new requirement that is ill-considered?