If/when I buy a subscription, how long until it applies to my site?

Is there anything I need to do on the backend of the website, etc?  Or will it just work?

Hi,

Your subscription should be immediate.  Occasionally if a users uses a different email address for their billing though, the subscription may not be properly applied.  If you do upgrade and do not see the change reflected in your account fairly quickly, let us know and we will be happy to manually apply it.

There is nothing you need to do other than upgrade.