During 2022 we've been on a mission to completely rework the slowest bits of Matrix, aiming that nobody can ever complain about Matrix being sluggish again. In practice this means fundamental changes in:

• how Matrix syncs data - "sliding sync", where servers only sync the bare minimum data to clients required to render the UI, providing instant login and instant sync (MSC3575)

• how room joins work over federation - "faster joins", where servers only sync the bare minimum data such that clients can start participating in the room as soon as possible (MSC3902)

• how auth works - switching Matrix to use OIDC natively for all authentication, registration and account management (MSC3861)

• how VoIP works - switching Matrix to natively support multiparty decentralised E2EE VoIP as the primary calling mechanism (MSC3401 and MSC3898)

The end result is transformational, and by far the biggest change to Matrix since the project began in 2014. So, we're calling it Matrix 2.0, and this talk will give a guided tour of everything that's changed - and show off the new reference matrix-rust-sdk client SDK, which powers the new flagship mobile Matrix client, codenamed Element X.