If you paid attention to last week’s Apple event, you might already have September 16th marked off in your calendar. Even if you didn’t, your iPhone will remind you that it’s a special day by displaying a little red circle on the top-right corner of your Settings app. This can only mean one thing: a shiny new iOS update.

Wednesday marks the release of iOS 9, and the new mobile OS has a ton of cool features. Although it ships out with the new iPhone 6s and 6s Plus, those of us who haven’t committed to a new iPhone can also upgrade. Here’s what to do to get iOS 9 running on your device.

1: Check Compatibility

Even if your iPhone or iPad is nearing its fourth birthday, you can probably still upgrade. iOS is compatible with devices as old as the iPhone 4s, iPad 2, and 5th generation iPod touch. Newer models are also compatible (of course). For the most part, any device that was compatible with iOS 7 is also compatible with iOS 9 (sorry iPhone 4).

2: Back Up

Because no update is perfect, it’s always a good idea to back up your device. You can back up iOS devices by using iCloud or your computer.

If you are backing up via iCloud, go to Settings > iCloud > Backup. Next, make sure “iCloud Backup” is turned on, and hit “Back Up Now” (keep in mind that you need to be connected to Wi-Fi to do this). To check if the back up worked go to Settings > iCloud > Storage > Manage Storage, then choose your device. Once you do this you’ll see your most recent back up.

If you are backing up your device through your computer, connect your device and open iTunes. Next go to File > Devices > Transfer Purchases, and when that’s done go to File > Devices > Back Up. You may also want to back up your pictures and videos.

For more information on what is and isn’t backed up, check Apple’s support document for iOS updates.

3: Free Up Storage

Updating your device requires free space. This tends to be a source of panic for those of us who have filled our 16GB iPhones to the brim. To find out which apps are eating all of your precious storage go to Settings > General > Usage > Manage Storage. Now is a good time to delete all those apps you never use, and transfer your media files to your computer for safe keeping.

4: Update Away

Starting Wednesday, September 16, you’ll have two ways to update to iOS 9. The easiest way is by updating through your device. First, make sure you have enough battery life by plugging into a power source, then go to Settings > General > Software Update > Download and Install. After the iOS 9 package is downloaded, an alert will pop up giving you the option to install now or later. Keep in mind that your device will restart when installation is finished, and you won’t be able to use it during the installation.

If you don’t have enough storage to update over the air, you can also update using iTunes. To do this make sure you have the latest version of iTunes installed, then plug your device into your computer. When your device pops up in iTunes, look for the Summary box. Hit the “Check for update” button, then download and update.