Redesigned Notification Pulldown Bar
In Oreo Google completely redesigned the notification pulldown bar. Instead of the old dark color scheme, it's now black and white. Icons and information is easier to see, and they moved the date, time and battery levels. Depending on who makes your phone, you may or may not see this change.
Shown above you see Nougat on the left. It's dark and hard to read, while on the right everything is clear.
On Oreo, the date is under the quick setting icons and the battery levels and clock are smaller and to the top right. You'll also notice the gear-shaped settings button is in a new spot. Now the multi-user accounts, edit mode, and settings icon are at the bottom right side of the pulldown bar. I guess this is easier to press, as it's no longer a stretch to the top of the screen.