Do I Need a Zen License?
Maybe not. Login as a site administrator and visit the Admin Console > Zen Foundation > License screen to find out.
Or if you already have Zen installed, look in the Zen toolbar at the top of the screen, to the left of your name. If you see the message "Zen Foundation is not licensed" then your installation needs a license to use Zen:
Free Licenses
If you're running a commercial or academic Confluence license, you can get a free evaluation license for Zen Foundation here.
For community or open-source licenses, you need to register through the Atlassian Marketplace for a free Zen license (the easiest way is to click Zen's "Buy" button in your Confluence Plugin Manager after installing it.). (Not required for Zen 4.x)
And yes, evaluators are entitled to technical support for Zen.
Example
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