See my PM. Do you mean warnings or errors? If you mean warnings, Unity 2019 has a problem that originated from the recently adopted Roslyn compiler where any serialized properties (i.e. stuff you set in the inspector) generates warnings if it is not explicitly set in the script. See the issue tracker here. This is ridiculous and must be fixed. Apparently Roslyn has been updated with a way to fix the issue, but Unity has not implemented it yet, see this thread.