1. Post Questions
2. Reuse Assignments
3. Improved Calendar Integration
4. Bump a Post
5. Due dates optional
6. Attach a Google Form to a Post
7. YouTube Functionality

For more information: http://www.teachthought.com/google-2/changes-new-features-in-google-classroom/
http://googleforeducation.blogspot.mx/2015/08/head-back-to-school-with-new-features-in-Google-Classroom.html?m=1