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  The new Gmail. It's blue and has a big sidebar, but there are options to tweak both of these big changes. [credit: Google ]

Starting this month, users who have been holding out on the new Gmail design introduced earlier this year will be forced to switch .

The latest design was first introduced as an opt-in update in February and then became opt-out this summer. Now it's just Gmail, full stop.

The design didn't change too much about how Gmail works; it mostly just changed the color scheme—gone is the Gmail-brand red styling in favor of a more neutral and blue-ish-by-default look in line with the company's "Material You" design principles. You can tweak the coloring yourself anyway.