Updating a Chromebook
Chromebooks should update automatically, but if you want to force it to update or just check to make sure you have the latest version you can follow this guide
Turn on your Chromebook.
At the bottom right, select the time.
Select the gear for Settings.
Select the three horizontal lines for Menu and then Select About Chrome OS.
Under "Google Chrome OS," you'll see which version of the Chrome operating system your Chromebook is using.
Select Check for Updates.
If your Chromebook finds a software update, it will start to download automatically.
Once it's done,
Once any updates are done, you can look in the "About" window to confirm that your Chromebook is up to date.