Product licensing
Starting with version 3.2, the syslog-ng Open Source Edition application is licensed under a combined LGPL+GPL license. The core of syslog-ng OSE is licensed under the GNU Lesser General Public License Version 2.1 license, while the rest of the codebase is licensed under the GNU General Public License Version 2 license.
NOTE: Practically, the code stored under the lib directory of the source code package is under LGPL, the rest is GPL.
For details about the LGPL and GPL licenses, see GNU Lesser General Public License and GNU General Public License, respectively.
For clarity, the Documentation is licensed separately. For details, see The syslog-ng Open Source Edition Documentation License.