Follow these steps to manually update Chromebooks.
On the sign-in page, Press Alt + V.
The OS version and serial number will display in the top right corner of the screen.
If the Chromebook does not have the latest OS version, try to do a manual update.
Sign-in to your Chromebook and click on the time.
Click on Settings.
Click on About Chrome OS.
Click on Check for updates.
Wait for the Chromebook to download the update, then Restart the Chromebook to install the update.