New Google Groups
September 16, 2020
Starting around September 15, 2020, Google will make new Groups the default for all users.
The new groups featuring an updated interface and more streamlined controls that make it easier to create, manage, and use. The modern interface is similar to other G Suite apps, such as Gmail, and makes Groups more efficient for new and existing users.
You will see new Groups by default when you go to groups.google.com but can revert to classic Groups at any time. Sometime after October 15 the old Groups will be turned off and you will not have the option to revert.
Visit Google's help page on Groups.