1. Backup
2. Delete old folder "Assets/OSA" (You need this because importing unitypackages doesn't remove files that are not needed anymore)
3. Import new package. 
4. If you previously imported the Utils, Demos or any other sub-package, re-import it now.
5. [Optional] Fix some warnings about variables never used (In our project we have set some warnings as errors, so we needed to fix these warnings in order to compile the project again)