Hi,
My personal opinion is not to switch a project from 4x to 5x. This doesn't make sense in practice, so start a new project in 5, yes, ok, but updating from 4x to 5x knowing how much changes, is dangerous, especially when physics is involved. If you have games and project not using Rigidbodies, then you can attempt it.
also, make sure you double check the
troubleshoot, typically, the only problem is the way unity packages now rely on internal ids as opposed to filename ( as I understood it), and so a clean deletion of PlayMaker and re import is necessary in some cases ( not every case, I haven't had any of my personal project exposing these issues yet).
Bye,
Jean