Android Pie is here, and one of its biggest features is the new navigation gestures. The new gestures are a welcome touch, but if you can't live without your Home, Back, and Recents buttons, you've got nothing to fear for the time being.
When you update your phone to Pie, the gestures are turned off by default. If you want to enable them, you've got to go to Settings -> System -> Gestures -> Swipe up on Home button.
However, things won't always be this way. Starting with the Pixel 3, new phones that ship with Android Pie out of the box will have gestures turned on by default with no way for users to revert to the traditional buttons.
Forcing everyone to adopt the gestures might seem a bit heavyhanded, but that's the only way Google's going to be able to improve upon them and make them even better than they are in their current form.
Plus, with just a little practice and patience, the gestures quickly become to feel a lot more natural and fluid than tapping away at virtual buttons.