Checking for Chrome OS updates manually:
• Turn on your Chromebook.
• Connect your Chromebook to Wi-Fi.
• Sign in to an account.
• At the bottom right, select the time.
• Select Settings.
• At the bottom of the left panel, select About Chrome OS.
• Select Check for updates.
• If your Chromebook finds a software update, it will start to download automatically, and it will ask you to restart after install.