ZenTao is a Scrum tool which is licensed under ZPL 1.2. 

The key feature of ZenTao:

1. Product management(product backlog)

   story management
   plan management
   release management

2. Project management(sprint backlog)
   
   task management
   team management
   build management
   burn down chart

3. QA management

   bug tracking
   test case management
   test task management

4. Document management

5. User management

6. Todo management 

ZenTao official website: https://www.zentao.pm/
ZenTao demo site: http://demo.zentao.pm/