For almost 5 years now Google has been stating that the old, “traditional” variation of Google Sites would be closing “soon.” It appears that they really suggest it this time. In an e-mail to Google Workspaces domain administrators and in
this article, Google has actually announced that on May 15th the capability to produce new sites utilizing the old version of Google Sites will be removed. Then on December 1st modifying of sites made with the classic variation of Google Sites will be disabled. And on January 1, 2022 all websites made with the classic variation of Google Sites will be offline..

Shift from Classic Google Sites to Current Google Sites.
People who are still utilizing the classic variation of Google Sites can shift to the current version of Google Sites by following the instructions in this video. It must be kept in mind that not all functions discovered in the traditional variation of Google Sites are available in the existing version of Google Sites..
Develop a Website with Google Sites.
The current version of Google Sites is much easier to utilize and more aesthetically pleasing than the timeless version. And there are some practical features in the existing version that were not offered in the classic version.

Three Quick Ideas for Using Google Sites in Your Classroom.