Based on improvements and new features this year the top 3 Open Source Project Management Tools for 2016:
3) OpenProject -is designed to help your project teams throughout the entire project lifecycle and gives collaborative project planning, timeline reports, task management, time and cost reporting, Scrum, and more. OpenProject stands out with its intuitive user interface, extensive documentation, API, and rich feature set, which makes it a good choice for enterprise needs. OpenProject is currently working on version 5.1, which will bring inline work package creation, design and usability improvements, accessibility improvements, and more. Benefit from powerful project management features, Create and manage tasks, bugs, change requests, requirements, risks, and more. Set up and maintain project plans based on your needs. Organize meetings, documents, and track time and costs. 100% Accessible. 100% Open Source. OpenProject is licensed under GPLv3. Its current version 5.0.16 is available for download.
2) LibrePlan - is a web-based application, making project management available to the whole project team, and if necessary across organizations. This is another full featured tool supporting resource allocation, Gantt charts, financials. Manage Resources, Track Data, Collaborate and more. LibrePlan provides a modern design and balanced user interface, as well as, good and complete documentation, built in reporting, and professional support. A mobile application is available for Android, Windows phone, and other platforms. LibrePlan is licensed under GPLv3. It requires components a Java runtime environment, PostgreSQL, and Tomcat. Its available for download, and the source code can be found on GitHub.
1) ProjectLibre - an award winning tool championed as the open source replacement of Microsoft Project which has been downloaded over two million times in 200 countries. It holds features such as support for task management, resource allocation, tracking, Gantt charts, and more. Als0 ProjectLibre Enterprise Cloud will release soon and have a similar disruptive impact that Google Docs had with Microsoft Word! ProjectLibre is licensed under a Common Public Attribution License Version 1.0. It's based on Java, and available for download.