The update is being offered OTA (Over-the-Air) and users should receive a notification when it is available for their devices. You can also manually check for the update by heading over to Settings > About tablet > Software Updates.
If you don’t want to wait for the update you could consider manually updating your Motorola Xoom to Android 4.1.2 using the following process:
[NOTE] The first guide is for users who have not rooted your devices. Ensure you have the Android SDK or a tool which can invoke ADB commands
- Download the Android 4.1.2 Jelly Bean (JZO54K) update file for your Motorola Xoom (Wi-Fi).
- Connect your device to your computer.
- Reboot and enter Android Recovery mode using the command adb reboot recovery.
- Open command prompt (CMD in Windows, Terminal in Linux or Mac) and type the following:
adb sideload 75baa1719d30.signed-tervigon-JZO54K-from-JRO03H.75baa171.zip
- Once the file has been transferred to the device you will get a message similar to the following:
sending: 'sideload' 100%
- The update should now start installing on your device.
- Once setup is complete, reboot and you should now have the latest version of Android on your Motorola Xoom (Wi-Fi)
If you have rooted your Motorola Xoom, you can Download the rooted version of the Android 4.1.2 JZO54K OTA update and find the instructions on installing the files by following the source link.
The update will mainly offer bug fixes and performance improvements for the Xoom, along with the ability to expand/collapse notifications with one-finger gestures.
source – XDA