Purchase and Activation of 3rd party Extension Keys from Plesk We provide third-party extension keys from Plesk for products such as: CloudLinux KernelCare Acronis Backup Imunify360 You can purchase these keys in RCP from: Plesk Licenses >> Order New Plesk License >> Third Party Extension Keys >> Order >> Select product type and period, then click on Order now Activation Process Once the order is placed, the activation key will be sent to the reseller. Log in to your Plesk panel. Go to Tools & Settings → License Information (previously 'License management'). Enter the activation key to install the product.