Having tried the demo version of the product you can register it and upgrade it to the commercial version.
To do so, you have to:
Buy the license.
Introduce your license key:
On the tab Install updates (Marketplace > Platform Update), by clicking Enter license key.
On the tab Update system of the setup page Kernel module (Settings > System settings > Module settings > Kernel module) in the License key box.
After that, the key activation process shall be launched according to the instructions given in the lesson Registering a commercial version. Upon the completion of commercial registration, the demo version limitation on the operating time will be lifted, and you will obtain the full product.