YouTube disables classic web design

YouTube announced the termination of the classic design of the web version of video hosting. It will be permanently disabled in March 2020.

In August 2017, YouTube redesigned in the Material Design style and with an optional dark theme, but for almost three years, users could stay with the old version of the interface.

The old version lacks many of the new design features and improvements that we introduced over the past three years, including innovations based on your most popular requests.

Now the site will begin to display a notification about the need to upgrade to a modern version of YouTube. It does not support some outdated browser releases, so the service will offer to update the client if necessary.

Source: Google Support