[caveat]
I am a casual Feng Office user with no knowledge of this beyond what I've read on the website and forums
[/caveat]
The Feng Office download from SourceForge is the 'Community Edition', which is free for you to install and use on your own hardware.
The pricing plan covers hosted service, or managed service on your hardware (see www-dot-fengoffice-dot-com/web/buy-onsite.php).
The Feng team stays pretty busy, so fixes and new features are more likely to make it into the core if you pay to get them there.
The paid, 'Professional' version also seems to include some non-open-source add-ins that increase functionality.
What Open Source license does Feng Office use?
Feng Office Community Edition is AGPLv3. That means you can do pretty much anything with it - with a few obligations.
The Professional Edition Suite bundles several add-ins that are not Open Source licensed. We encourage Businesses that plan to offer Feng Office-based services to contact us and seek a Partnership agreement.
For those who do not want to officially partner, we recommend you research the rights and obligations of the AGPLv3 license carefully.
