Open CCleaner and click the Check for updates link in the app to see if you're on the latest version. You can also go to Options > Updates > Control product updates for CCleaner
How to update CCleaner manually:
Following the steps above, click on the Check for updates link at the bottom right-hand corner of your CCleaner window. It should be there no matter what CCleaner app screen you're on (see the screenshot for reference).
If there's a newer version available, CCleaner notifies you and gives you the option to download it.
You can also change your update options at any time via Options > Updates > Control product updates for CCleaner (see the screenshot for reference).
You can find out more here.
It may take a day or two for updates to apply when using automatic updates.
There are no additional charges for each update.