After you install Plesk, a trial license key for 14 days is installed by
default. To continue using Plesk after the trial license key expires,
you should obtain a lease license key or purchase a permanent license
key.
A leased license means that you pay for a limited time during which you
can use Plesk, for example, two months. During the lease period, Plesk
will perform free monthly updates of your license key. The lease license
includes free upgrades to all major new versions of Plesk.
The permanent license means that you buy a lifetime Plesk license. A
permanent license is updated every three months for free. Upgrading a
Plesk installation with a permanent license to the next major version
requires a separate payment unless you use Software Update Service
(SUS). See https://kb.plesk.com/en/111 for more information on SUS.
Plesk license keys have a grace period of 10 days before the
expiration date. During the grace period, Plesk makes daily attempts
to update the license key automatically. If an automatic update fails,
Plesk notifies the administrator. If you do not update a license key
during the grace period, it expires and blocks Plesk functions until you
install a valid license key.
Plesk defines whether it needs to update the license key using the
update-keys.php utility located in the
$PRODUCT_ROOT_D/admin/plib/DailyMaintainance/ directory, where the
$PRODUCT_ROOT_D is /usr/local/psa. This utility checks the
license grace period and expiration date and tries to retrieve a new
license key or blocks Plesk.
Plesk runs the utility every day as a part of the daily maintenance
script. If you want to check for license updates, you can run the script
manually by executing the command
$PRODUCT_ROOT_D/bin/sw-engine-pleskrun $PRODUCT_ROOT_D/admin/plib/DailyMaintainance/script.php.
You can retrieve and manage license keys through the Plesk GUI. The
information about the current license key and controls for managing
license keys are located in Server Administration Panel > Tools &
Settings > License Management.