The trial is valid for 15 days. You'll have a fully featured XOA in Premium state!
We don't have other edition for trial, but you can compare features on our pricing page.
In your current Free XOA, go register it in the "Updates" view in the main menu:
To register, please use your email/password from your previous registration on xen-orchestra.com:
There, you can click on "Start Trial" green button:
Remember to click on Upgrade button after requesting the trial, to download the Premium Edition for 15 days!
In this update view, you can see when your trial will end:
Don't worry! XOA will still work after the trial: you'll be forced to downgrade to Free version, but you won't lose any configuration.