Plesk license determines

• What Plesk functionality is available when using a particular Plesk instance
• How many Plesk logical objects (Customer accounts, Domain accounts, mailboxes, web users, etc.) can be created in a particular Plesk instance

Plesk Administrator has full set of privileges required for managing Plesk license. The following operations are available via Plesk XML API protocol:

• Retrieving information on the currently installed Plesk license key
• Installing new license key
• Reverting to a previously used license key
• Installing additional keys (required for Plesk add-ons) linked with the Plesk license key
• Retrieving additional keys installed on the server