[@chrishajer Participant 16 years, 2 months ago]

phpBB3 > phpBB2

http://www.arvystate.net/e107_plugins/content/content.php?content.30

phpBB2 > bbPress

https://bbpress.org/forums/topic/a-phpbb-to-bbpress-database-converter

I don’t think there’s any how to written for the complete process. You could be the first.