Revision history [back]

ZK 3 and prior versions will continue to be distributed under the GPL license. The GPL license only allows compliant open source applications to use the licensed software/framework. To allow our community more freedom, ZK 5 has moved to the LGPL license which is free for both open source and commercial projects.

We are very committed to open source and took onboard everyone’s opinion making ZK 5 Professional and Enterprise editions completely free for use within open source projects. I believe it is about striking a balance and think that we have definitely achieved this.

As for ZK Calendar, like ZK 3, it has always been licensed under GPL and will continue to be.