Google launches the "New Gmail" for everyone:

Google launches the "New Gmail" for everyone: here is how you enable or disable it - June 15, 2021 

Last year, Google revealed plans to turn Gmail, the company's popular email service, into a communication and work powerhouse by introducing chat, video calls and Google Docs functionality.

Today's announcement on the official The Keyword website marks the launch of the new Gmail.
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Gmail users who don't want the new interface can keep it turned off for now. It remains to be seen for how long that option will be available. It seems likely that Google is going to promote the new functionality on Gmail eventually, e.g. by showing popups to users prompting them to switch to the new interface and functionality.

https://www.ghacks.net/2021/06/15/google-launches-the-new-gmail-for-everyone-here-is-how-you-enable-or-disable-it/