So this is a pretty big deal to me (it looks recent, just put up last October). One of my big frustrations with Matrix was that they didn't offer helm charts for a kubernetes deployment, which makes it difficult for entities like nonprofits and community clubs to use it for their own purposes. Those entities need more hardware than an individual self hoster, and may want features like high availability, and kubernetes makes horizontal scaling and high availability easy.
Now, according to the site, many of these features seem to be "enterprise only" — but it's very strangely worded. I can't find anything that explicitly states these features aren't in the fully FOSS self hosted version of matrix-stack, and instead they seem to be only advertised as features of the enterprise version
My understanding of Kubernetes architecture is that it's difficult for people to not do high availability, which is why this makes me wonder.
Looking through the docs for the "enterprise version, it doesn't look like anything really stops me from doing this with the community addition.
They do claim to have rewritten synapse in rust though
Being built in Rust allows server workers to use multiple CPU cores for superior performance. It is fully Kubernetes-compatible, enabling scaling and resource allocation. By implementing shared data caches, Synapse Pro also significantly reduces RAM footprint and server costs. Compared to the community version of Synapse, it's at least 5x smaller for huge deployments.
And this part does not seem to be open source (unless it's rebranded conduit, but conduit doesn't seem to support the newer Matrix Authentication Service.)
So, it looks Matrix/Element has recently become simultaneously much more open source, but also more opaque.
It's worth noting that the ESS suite Chart is absolutely not built to be community-viable, it's built for the kind of single-purpose deployments that Element offer hosting for, and it also breaks almost all Kubernetes best practices. Which is actually not wrong per-se. Element need to be able to maintain it after all, and since they don't have the Kubernetes know-how to build generic components, it makes sense to instead bundle a fully integrated solution which they are comfortable with developing and debugging.
They're definitely slowly but steadily rewriting Synapse in Rust as well, that's been an open and ongoing project for a while now. You can see that just by looking in the Rust folder in the Synapse sources.
I strongly doubt that they have the "rest" of the application rewritten internally and keeping it hostage for paid hosting though, it'd cost them too much to keep separate codebases for such a thing.
The "Synapse Pro" offering is most likely just the regular Python+Rust Synapse, but with a few additional HA components and some workers written in Rust for efficiency, just like how there's community workers written in both C# and Go for performance reasons.