Paid for upgrade but message says "7 days remaining" or "Buy now"

I am using a trial of "Pro". I've just paid for an upgrade to "Pro" but I still get the "7day" warning. Will the upgrade happen automatically when the trial expires?

You need to register/activate CCleaner Pro using the individual licence key that was sent to you in your confirmation email.

See this for how to do that:

https://support.piriform.com/hc/en-us/articles/204043844-How-to-register-and-activate-CCleaner-Professional