Apple has spent the last few months talking up a range of new emojis. There's an emoji of a bearded person, a T. rex, a zombie and an explodey head for those times you just can't believe what you're being told.
Another notable change after following the instructions below is the 3D touch multitasking gesture, where you press on the left edge of the display, has made a comeback.
In order to get the new emoji and multitasking goodness, all you have to do is install. Make sure you're on Wi-Fi, and go to Settings > General > Software Update.
After the update, all of the new emojis will be in the usual place. The only downside is that only people who are also on iOS 11.1 will be able to see them.