The outbox model still needs to gain significant adoption across Nostr's most popular clients. I had hoped that by the end of 2024 we would see mass adoption. The clock is ticking to meet this goal, but I feel we're on track.

Why is this important?

This will shift the focus away from relying on a small number of dominant relays, leading to a more decentralized and resilient network. Beyond increasing decentralization, the implementation of the outbox model significantly contributes to the long-term sustainability of the Nostr protocol too.

This is achieved by alleviating the burden on relay operators, who would no longer require substantial resources to maintain large-scale infrastructure. This paves the way for long term, small community focused relays. Small relays such as Nostr Team Relay or Ditto powered instances could be part of Nostr's core future.

No longer would users need to center upon the top relays to communicate. Individuals could run their own private relay and only post to their own private relay and/or a couple others.

Which clients have support?

Clients perform the heavy lifting here, facilitating all of these improvements. Several already do, and others are working on implementation.

Full or partial support:
Gossip
Snort 
Iris
Coracle
Nostrudel 
Lume
Amethyst 
Highlighter 
And any applications built with NDK.

Future support:
Damus, including Notedeck
Primal

If this list is inaccurate or needs updated please let me know.