User blog comment:Brandon Rhea/Introducing Unification, FANDOM's next big initiative/@comment-3338841-20181003011024/@comment-20644-20181008224026

Chat in its current form is not mobile compatible. It was built in a time where mobile just wasn't a focus or something we developed for. To add Chat to mobile, we’d essentially have to build a new Chat feature.

That being said, Chat is something we've been thinking about and discussing internally in terms of how (and if) we want to approach direct messaging and group chats in the future. No plans yet, but once we know more we can talk about it here.