https://pkp.sfu.ca/ocs/

Open Conference Systems (OCS) is a free Web publishing tool that will create a complete Web presence for your scholarly conference.

https://github.com/olatsystems/OpenOLAT

https://moodle.org/

Moodle is a free, online Learning Management system enabling educators to create their own private website filled with dynamic courses that extend learning, anytime, anywhere.

https://sourceforge.net/projects/cce-interact/

https://docu.ilias.de/ilias.php?baseClass=ilrepositorygui&reloadpublic=…

https://www.formalms.org/

Forma Lms is an open-source, web-based elearning platform (Learning Management System - LMS), used to manage and deliver online training courses.

http://www.bndlg.de/~jonny/projects/wboard/index.html

WBoard allows you to run several WWWBoard-style forums on your website. Messages are stored in 3 tables and are searchable.

http://www.viscacha.org/

https://vanillaforums.com/en/software/

Simple and flexible forum software. Great for enthusiasts and small businesses.

http://newsboard.unclassified.de/