Project Save Manager
Engine Version 6000.0.x → 6000.3.x
Project Version 3.0.7
Project Version Fixed In 3.0.8

Summary

The project fails to compile in Unity 6 to 6.3 due to API used in a contribution not been supported in the earlier Unity 6 versions.

Cause

If defines for some Unity 6 API set to 6000.0 not 6000.4 as needed for the specific API.

Resolution

Update to 3.0.8 or newer to receive the fix.