To sign up for the Gradebook & locked mode in quizzes Beta click here to fill out the Google form.
To read Google's blog post regarding the new gradebook and locked quizzes using Google forms - click here.
Embedded below is Google's tweet regarding the new gradebook.
📝You asked, we listened! Grading in #GoogleClassroom just got better. Teachers can now view submissions across classwork & students, view & customize average grade calculation, and add weighted grade categories. Sign up for the beta: https://t.co/6zxdlJJHgM pic.twitter.com/NdZIF2jnQj— Google For Education (@GoogleForEdu) November 29, 2018