This motion whitelists the System.authorizeUpgrade call for the nexus-v8200 runtime so it can be dispatched via the Whitelisted Caller track on OpenGov.

Call Details

• Call: Whitelist.whitelistCall(callHash) (pallet index 83, call index 0)
• Encoded call: 0x00091e45b50cdfb9b90eab07bf3c83125300cf2dd911a2a02e6f1eec4957e1ec5bd5
• Call hash (keccak-256): 0xc842c4dd0714ff1c1dcde5c27216f8561ef47d1ec75b3e59ef93abdb5f8942f6
• Encoded Whitelist.whitelistCall: 0x5300c842c4dd0714ff1c1dcde5c27216f8561ef47d1ec75b3e59ef93abdb5f8942f6

Runtime Details

• Release: nexus-v8200 (published August 1, 2026)
• Commit: c28fc0eb42ccde3091830ac5b38c4a1a0f0c066b
• Spec version: 8200 (nexus-8200 nexus-0.tx1.au1), upgrading from 8000
• WASM file: 2,082,839 bytes (1.99 MiB)
• Keccak-256 hash: 0x1e45b50cdfb9b90eab07bf3c83125300cf2dd911a2a02e6f1eec4957e1ec5bd5
• Toolchain: rustc 1.91.1 (ed61e7d7e 2025-11-07)

What's Changed

polkadot-sdk stable2606 upgrade

The largest part of this release by volume. It moves the runtime onto the stable2606 SDK line, which changes several runtime API signatures:

• SessionKeys_generate_session_keys now takes an owner argument and returns OpaqueGeneratedSessionKeys, carrying a proof of possession over the owner account
• a new KeyToIncludeInRelayProof runtime API is implemented, returning empty because this runtime reads no extra relay chain storage
• pallet_scheduler gains SchedulingSignatureVerifier, set to ()

Anything that calls author_rotateKeys against a node running this runtime should be checked against the new session keys signature. This mainly affects collator operators.

Dispatchable XCM execute turned off

XcmExecuteFilter moves from Everything to Nothing, so PolkadotXcm::execute no longer accepts locally dispatched XCM programs. XcmReserveTransferFilter was already Nothing; XcmTeleportFilter and SafeCallFilter are unchanged at Everything.

GRANDPA consensus proofs bound to the tracked state machine (#1069)

ismp-grandpa now checks that the shape of an incoming consensus message matches the state machine the client is configured to track, before any verification arm runs. A relay chain proof submitted against a parachain tracker, or the reverse, is rejected up front with ConsensusMessageStateMachineMismatch rather than being routed into a verification path that was never meant to receive it.

Mandatory proofs

Mandatory consensus proofs that do not advance a parachain's height are now accepted rather than discarded, and mandatory proofs are stored under their own offchain namespace so they no longer share key space with ordinary proofs.

ByteVector length validation on SCALE decode

ByteVector now validates its declared length while decoding instead of trusting it.