This proposal authorizes and enacts the nexus-v8400 runtime upgrade, published at https://github.com/polytope-labs/hyperbridge/releases/tag/nexus-v8400.

Runtime details

• Spec: nexus-8400 (nexus-0.tx1.au1), metadata V14, transaction_version unchanged at 1
• Keccak-256 code hash: 0xf9def0b3590aa15b144c2f7108555c935d803c22d9e819212eab6afc4dec7b08
• Size: 2.01 MiB (2,104,678 bytes), built with rustc 1.91.1
• Reproducible with ./scripts/build_release_runtime.sh nexus-runtime

Changes included

• Bound proof-verification inputs before doing the work (#1120) — the EVM state machine and Pharos SPV verifiers now validate and bound proof inputs up front, so malformed or oversized proofs are rejected before any expensive verification is performed.
• Reject purchases whose app identifier exceeds AppKey (#1126) — bandwidth purchases carrying an over-long app identifier are rejected instead of being silently truncated, keeping the on-chain and Solidity-side accounting keys in agreement.
• Per-chain phantom order configuration (#1127) — the intents coprocessor's single global phantom order config becomes a per-chain storage map, allowing parameters to be tuned independently per destination chain. Includes updated benchmarks and weights.
• Runtime version bump (#1109) — sets spec_version to 8400.

Storage migration
This upgrade runs pallet_intents_coprocessor::migrations::MigrateConfigToStorageMap, which moves the existing global phantom order configuration into the new per-chain storage map. The migration is bounded and guarded by the pallet's storage version.

Enactment

1. system.authorizeUpgrade(0xf9def0b3590aa15b144c2f7108555c935d803c22d9e819212eab6afc4dec7b08)
2. system.enactAuthorizedUpgrade(code) with the WASM artifact from the release page.