I can’t update my Apple Watch

First, see if your watch is compatible with the latest software updates :

First, make sure that your Apple Watch works with the latest software. watchOS 9 is compatible with these Apple Watch models:

• Apple Watch Series 4 and later
• Apple Watch SE (1st generation) and later
• Apple Watch Ultra

Updating to watchOS 9 also requires one of these iPhone models:

• iPhone 8 or later with iOS 16
• iPhone SE (2nd generation) or later with iOS 16

If your Apple Watch isn't compatible with the latest version of watchOS, Software Update will show you the newest version that your watch can use.

Next, check these things:

1. Make sure that your iPhone is updated to the latest version of iOS.
2. Make sure that your Apple Watch is at least 50 percent charged.
3. Make sure that your iPhone is connected to Wi-Fi.

Then follow these instructions to update

You can wait until Apple Watch notifies you when a new update is available. Tap Update Tonight in the notification, then go to your iPhone to confirm that you want to update overnight. At the end of the day, leave your Apple Watch and iPhone charging overnight so the update can complete.

Or you can update your Apple Watch with your iPhone manually:

1. On your iPhone, open the Apple Watch app, then tap the My Watch tab. 
2. Tap General > Software Update.
3. Download the update. If asked for your iPhone passcode or Apple Watch passcode, enter it. 
4. Wait for the progress wheel to appear on your Apple Watch. It could take from several minutes to an hour for the update to complete. 

You can also update directly from your watch: If your Apple Watch has watchOS 6 or later, you can install updates without your iPhone:

1. Make sure that your watch is connected to Wi-Fi.
2. On your watch, open the Settings app.
3. Tap General > Software Update.
4. Tap Install if a software update is available, then follow the onscreen instructions.

It's important to keep your Apple devices up to date so that they have the latest bug fixes and security enhancements. 

Some iOS updates on your iPhone require that you also update watchOS on your Apple Watch. So if you see an alert on your iPhone that says "Update Apple Watch" and "Your Apple Watch software is out of date," you should update to the latest version of watchOS so that your data, including Activity data, continues to sync to your iPhone.