> They had their "pre-release" scheme going on for a very long time

They called them "developer pre-releases" even :-)

> the 4.1.7 "Final Edition"

4.1.8 :-)

http://amigaworld.net/modules/newbb/viewtopic.php?topic_id=39267&forum=16&start=160#742878
https://morph.zone/modules/newbb_plus/viewtopic.php?forum=3&topic_id=9932&start=6