The SDK's work is organized by MCP specification revision, with one GitHub project board per revision; each item is an issue or pull request you can follow.
v2 implements the 2026-07-28 specification and negotiates back to every earlier revision. Board: python-sdk · 2026-07-28 spec; the cross-SDK view is 2026-07-28 Spec Implementation. Still open there: making advertised capabilities configurable rather than pre-computed (#2896).
Of the extensions and optional client-auth mechanisms not yet implemented, those the conformance suite already exercises appear in its expected-failures baseline, .github/actions/conformance/expected-failures.yml, which burns down as each lands. The main ones:
- Tasks extension (
io.modelcontextprotocol/tasks, SEP-2663) — deferred at 2.0 because the 2026-07-28 design is wire-incompatible with the earlier in-core Tasks; tracked in #2806. - DPoP-bound access tokens (SEP-1932) in the OAuth client.
- The workload-identity
jwt-bearergrant in the OAuth client.
Everything else — bugs and smaller features — lives in the issue tracker, prioritized P0–P3. The SDK aims to release support for each new specification revision alongside that revision.
v1.x is a maintenance line: critical bug fixes and security fixes only. Support terms are in Versioning and support policy; the path off it is the Migration Guide.