The new Gmail launched over a month ago, but it was optional. By fall you’ll be using it whether you want to or not.
The new Gmail will also roll out to GSuite Users, though administrators will have some control over the timing. Here’s Richard Gao, writing for Android Police:
Eight weeks after the official rollout announcement in July, all users will be automatically updated to the new Gmail, though they’ll be able to opt out for another four weeks. But 12 weeks after the new UI is officially announced, all users will be migrated to it with no option to opt out. It’s a good thing that the new UI isn’t too controversial.
It’s true: there’s not a lot to complain about here. Sure, some people say the new Gmail is slow to load, and a few people couldn’t find Google Contacts. But these annoyances are balanced by a clever sidebar for your calendar and tasks, alongside features like Smart Compose, and offline support. Heck you can even @ people.
You can try the new Gmail right now, if you haven’t, by clicking the gear at top-right and then clicking “Try the new Gmail.”