User blog comment:MisterWoodhouse/Updates to Discussions and the plan for Forums/@comment-32042142-20200807185727/@comment-24155515-20200808000505

When a forum gets migrated to Discussions, they convert all of the already posted forum posts' raw HTML to Discussions posts that are properly dated and everything. No content is lost. (Except, presumably, if they were to be moving posts and find a post that was a TOS violation or something? But I've never seen that happen since it didn't happen for the forum on the wiki I run so I can't say for sure.)