In addition to Portal Community Edition ("Portal CE"), which is packaged for community users and developers and which is subject to an open source license under the GNU Lesser General Public License (LGPL), version 2.1 (for more information, see here), Liferay packages and makes available a supported Portal Enterprise Edition ("Portal EE"), intended for enterprise-grade users and implementations, which is subject to the Liferay End User License Agreement and made available to Liferay Enterprise Subscription customers at no extra charge.*
This "dual licensing" model is made possible by the manner in which Liferay manages the Portal open source project. Both Portal CE and Portal EE are based on the same open source and community developed software project. The source code added to the core repository of Portal is provided both by Liferay's software developers as well as community contributors. Liferay accepts code contributions for Portal from community developers only if the code passes Liferay's strict quality standards. Code contributors either license their contribution to Liferay or assign the contribution to Liferay. The result is a diligently managed code base and the freedom for Liferay to package and license Portal in ways that best benefit both community users and our enterprise-class customers.
Liferay Portal Enterprise Edition (Portal EE) is more suitable for use by enterprise-class customers and in mission-critical deployments than Portal CE. First, Portal EE is a hardened, stable and professionally supported build of the Portal software project. Secondly, Liferay has identified that for compliance-driven and risk-conscious companies, open source license compliance and management are major concerns. As Portal is a platform or framework intended for a user to build on to and extended through the user's own code, there are additional concerns related to the "viral effects" of certain "copyleft" open source license schemes. In response to these concerns, Liferay provides Portal EE under the dual licensing model described above. This approach significantly mitigates, for our enterprise customers, the costly and complicated burden of open source license compliance and management. With Liferay's Portal EE you have the freedom to customize your own solution and control your intellectual property.
Please note that in keeping with our core open source values, customers with a valid Enterprise Subscription have access the source code to Portal EE, including all updates, upgrades, security patches and service packs, etc., provided as part of Subscription services.
Ultimately, this "dual-licensing" approach allows our enterprise customers to get the "best of both worlds" in that their IT strategies can now take advantage of cutting edge and standards-based open source developed software provided as part of a larger Liferay Enterprise Subscription package that reduces the risks and burdens of open source license compliance and management.
For more information, the End User License Agreement (EULA) to Portal EE can be found here: www.liferay.com/legal.
* Enterprise Subscription customers enjoy access to Portal EE (and exclusive EE Apps and add-ons).