Earlier quoted context omitted.
This is the gap Snikket[1] is aiming to fill. A preconfigured XMPP server that you can safely and easily run yourself (it's invite-based registration), with "blessed" apps provided for each platform that are guaranteed to be maintained to a common standard. It's early days and there's still some way to go, but the current release (server + Android client) is receiving excellent feedback from those using it. The next…
Quick scan of the website & the github. Did not find direct mentions of XMPP. Does this interop with other XMPP systems or is this based-on-XMPP but standalone? I would not adopt or recommend this, framed as it is as it's own thing.
Snikket is aimed at people who primarily just want an out-of-the-box self-hosted secure messaging service. "XMPP" is not a feature for this crowd, but the benefits of XMPP are (federation, free choice of client software, etc.). For the same reason Mozilla doesn't advertise Firefox as a "HTTP client", the Snikket marketing is focused on features and not how the underlying tech is implemented - what we do, not how we do it.
The fact that Snikket is built on XMPP is not something we aim to hide however, it's discussed in [1] for example. It's just not what we lead with when introducing the project to general users.
Many good open-source projects fall into a trap of their developers marketing their project in a way that they would want to see it marketed to themselves. The truth is that nobody outside certain internet communities cares about open standards. They should, of course, but they don't realise it. We're trying to reach these people with Snikket.