In this release, we added the ability to add or remove keywords when you have selected multiple files and the files have different keywords.
In the Edit Metadata panel, you'll see +++ multiple values +++ in the Keywords field. Simple type over it, and put a + sign in front of a new keyword you want to add, or a - sign in front of the keyword you want to delete. Click the Save button to save the changes.
The Install script button is now back in the Startup & Delete page. Apple review team has approved this feature again in this release.