Once you have clicked on the + to create an announcement, assignment, or question - to the right of what class you are in - you will see where it says all students. Select the all students and you will see where the default is all students. You can then click where it says all students and then select the specific student (students) you would like to send it to.
The 2nd new feature is an e-mail notification when a student submits work past the due date. To make sure this is active in your Google Classroom...
1. Select the "hamburger" - the three lines at the top left of your home classroom page.