Hi Vincent, I deduced (possibly wrongly) that from the fact that there's only a Markdown Syntax 8.3 extension available, and the extension manager was not able to install said extension at all.
When I downloaded it and placed the jar into WEB-INF/libs, the container would not even start correctly, since it was missing the org/xwiki/contrib/rendering/markdown10/internal/parser/AbstractMarkdownStreamParser - after building and installing the 8.3 extension of markdown 1.1, there was a missing pegdown dependency and so on. And since github seems to have a 8.4-SNAPSHOT-Tag on the markdown parser, I assumed that so far, 8.4 has no support for it. Can you maybe tell me how to install it? Or is that because I already set markdown/1.1 as possible renderer in xwiki.properties?