If you are planning to expand your customer base and host more sites on the server than your current license allows, you need to upgrade your license key. All upgrades are applied to your main Plesk license key. Once you purchase upgrades at the Plesk online store, you will receive an activation email.

To upgrade the license key:

1. Contact your sales representative to upgrade your license.
2. When your license is upgraded, go to Tools & Settings > License Management > Plesk License Key and click Retrieve Keys.
3. The Plesk’s License Manager will retrieve the upgraded license key from the Plesk licensing server and automatically install it to your Plesk.