From the beginning, the Seafile server and Seafile syncing client’s source code are managed in one repository (https://github.com/haiwen/seafile). We thought this was more convenient since the client and the server share some common data structures (like commits, fs and blocks). The common code can be reused by both components.
But this also introduces some confusion about Seafile’s copyrights. The syncing client uses Git’s index data structure source code, which is under GPLv2. The server code doesn’t rely on GPLv2 code so it doesn’t have to be released under GPLv2. We still release it under GPLv2 so that we could keep the client and the server code in the same repository.
Now as the Seafile project becomes more and more mature and popular, we reconsider our earlier decisions. As a cloud storage server software, we believe the most suitable license for the community server is AGPLv3 instead of the old GPLv2.
Today we announce a separate project for the Seafile server core on github. The code is released under AGPLv3. Future development of Seafile server will be continued on this repository. From version 6.0.1 on, the community server will be built from this repository.
The change of license for the community server doesn’t affect the license of Seafile Professional server. The Seafile servers are released in a dual license model. The community server is in GPL, while the Pro server is in proprietary license.
Seafile Official Blog 