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Version: dev

v4.0.0 (from v3.0.0)

Overview​

Migration difficulty: TODO

Breaking changes​

Node.js upgraded to v24​

Node.js minimum version changed from v22 to v24.12.0.

Bot fee padding configuration renamed​

The bot configuration for fee padding has been renamed from "base fee" to "min fee".

v3.x:

--bot.baseFeePadding <value>          ($BOT_BASE_FEE_PADDING)

v4.0.0:

--bot.minFeePadding <value>           ($BOT_MIN_FEE_PADDING)

Migration: Update your configuration to use the new flag name and environment variable.

L2Tips API restructured with checkpoint information​

The getL2Tips() RPC endpoint now returns a restructured response with additional checkpoint tracking.

v3.x response:

{
  "latest": { "number": 100, "hash": "0x..." },
  "proven": { "number": 98, "hash": "0x..." },
  "finalized": { "number": 95, "hash": "0x..." }
}

v4.0.0 response:

{
  "proposed": { "number": 100, "hash": "0x..." },
  "checkpointed": {
    "block": { "number": 99, "hash": "0x..." },
    "checkpoint": { "number": 10, "hash": "0x..." }
  },
  "proven": {
    "block": { "number": 98, "hash": "0x..." },
    "checkpoint": { "number": 9, "hash": "0x..." }
  },
  "finalized": {
    "block": { "number": 95, "hash": "0x..." },
    "checkpoint": { "number": 8, "hash": "0x..." }
  }
}

Migration:

  • Replace tips.latest with tips.proposed
  • For checkpointed, proven, and finalized tips, access block info via .block (e.g., tips.proven.block.number)

Removed features​

New features​

Initial ETH per fee asset configuration​

A new environment variable AZTEC_INITIAL_ETH_PER_FEE_ASSET has been added to configure the initial exchange rate between ETH and the fee asset (AZTEC) at contract deployment. This value uses 1e12 precision.

Default: 10000000 (0.00001 ETH per AZTEC)

Configuration:

--initialEthPerFeeAsset <value>       ($AZTEC_INITIAL_ETH_PER_FEE_ASSET)

This replaces the previous hardcoded default and allows network operators to set the starting price point for the fee asset.

reloadKeystore admin RPC endpoint​

Node operators can now update validator attester keys, coinbase, and fee recipient without restarting the node by calling the new reloadKeystore admin RPC endpoint.

What is updated on reload:

  • Validator attester keys (add, remove, or replace)
  • Coinbase and fee recipient per validator
  • Publisher-to-validator mapping

What is NOT updated (requires restart):

  • L1 publisher signers
  • Prover keys
  • HA signer connections

New validators must use a publisher key already initialized at startup. Reload is rejected with a clear error if validation fails.

Admin API key authentication​

The admin JSON-RPC endpoint now supports auto-generated API key authentication.

Behavior:

  • A cryptographically secure API key is auto-generated at first startup and displayed once via stdout
  • Only the SHA-256 hash is persisted to <dataDirectory>/admin/api_key_hash
  • The key is reused across restarts when --data-directory is set
  • Supports both x-api-key and Authorization: Bearer <key> headers
  • Health check endpoint (GET /status) is excluded from auth (for k8s probes)

Configuration:

--admin-api-key-hash <hex>                 ($AZTEC_ADMIN_API_KEY_HASH)    # Use a pre-generated SHA-256 key hash
--no-admin-api-key                         ($AZTEC_NO_ADMIN_API_KEY)      # Disable auth entirely
--reset-admin-api-key                      ($AZTEC_RESET_ADMIN_API_KEY)   # Force key regeneration

Helm charts: Admin API key auth is disabled by default (noAdminApiKey: true). Set to false in production values to enable.

Migration: No action required — auth is opt-out. To enable, ensure --no-admin-api-key is not set and note the key printed at startup.

Transaction pool error codes for RPC callers​

Transaction submission via RPC now returns structured rejection codes when a transaction is rejected by the mempool:

  • LOW_PRIORITY_FEE — tx priority fee is too low
  • INSUFFICIENT_FEE_PAYER_BALANCE — fee payer doesn't have enough balance
  • NULLIFIER_CONFLICT — conflicting nullifier already in pool

Impact: Improved developer experience — callers can now programmatically handle specific rejection reasons.

Changed defaults​

Troubleshooting​

Next steps​