It's unclear when Google decided to discontinue Basic HTML support, but information about it can be found on this support page titled "Use the latest version of Gmail in your browser". 

"You can display Gmail on your browser in Basic HTML view until January 2024. After this date, Gmail automatically changes to Standard view," Google said. 

Moreover, the company mentioned on its support page that until January 2024, if you use an unsupported browser, you can open Gmail in Basic HTML view -- on your computer and your mobile browser. 

Meanwhile, Google is adding a useful "Select all" button to Gmail on Android, allowing users to clean up their inbox more easily and quickly. 

According to 9to5Google, Gmail for Android will start showing a "Select all" button when users start selecting multiple emails at once. 

This feature has been available on Gmail's web app for quite some time, but has never been available on mobile devices. 

While the name suggests that this will select every email in your inbox, it is actually limited to 50 -- the same as the web version, making it slightly less useful, but it's still a useful feature, the report said.