Answer: On your iPhone or iPad, go to Settings > General > Software Update
Ta-da!
Make sure you turn on "Replay" in your settings, and then you'll see the option to re-watch one lucky Snap a day.
Snapchat also introduced paid replays for $0.99 this fall
Press the power button and the home button at the same time
The keyboard shortcut is command-C for copy and command-V for paste
In the Apple Music app, press your account icon in the left-hand corner, then "View Apple ID," then "Manage" under subscriptions, then turn off "Automatic Renewal"
(See the step-by-step with pictures)
From the iTunes menu bar, click "Account" and then "Authorize This Computer"
If you have the latest smartphone software, you will have the newest emoji available for your OS
Microsoft ended up forcing everyone to upgrade, so this question no longer applies
There were a bunch of updates this year — here's how to use the new Lens feature