February 6, 2020
If a classic team site meets several criteria for being updated, the home page will automatically modernize the next time a user visits. When users first experience the change, they’ll see a walkthrough that highlights the new capabilities and includes a link to a help article with more details.
We encourage users to adopt the change in order to benefit from the power of modernized pages. However, if site admins or site owners want to revert to the classic home page, they can.
Read more here: http://bit.ly/2UmdMks
Posted by Eric Gregorich, Sr. Solutions Architect