Azul Upgrade Overview
Azul is the first Base-specific hardfork. It folds Osaka-era EVM changes onto the Base execution layer, trims the Flashblocks websocket payload, and turns on a multi-proof system that shortens withdrawal latency and lays the groundwork for stronger decentralization. It also drops support for non-Base clients.
What Azul ships
Section titled “What Azul ships”- Osaka EVM support on Base.
- A simplified Flashblocks websocket message format.
- A multi-proof system that unlocks faster withdrawals and a credible path toward decentralization.
- Base-native clients (
base-reth-node+base-consensus) as the only supported stack.
Activation timestamps
Section titled “Activation timestamps”| Network | Activation timestamp |
|---|---|
mainnet | 1779991200 (2026-05-28 18:00:00 UTC) |
sepolia | 1776708000 (2026-04-20 18:00:00 UTC) |
Both timestamps are now confirmed: Azul shipped to Sepolia first and activated on mainnet on 2026-05-28. Operators who have not yet moved to the Base-native stack should follow the Azul node upgrade guide to stay on the chain.
Execution layer changes
Section titled “Execution layer changes”The Azul execution engine page covers each of these in full; the list below links straight to the relevant section:
- EIP-7823: Upper-Bound MODEXP
- EIP-7825: Transaction Gas Limit Cap
- EIP-7883: MODEXP Gas Cost Increase
- EIP-7939: CLZ Opcode
- EIP-7951: secp256r1 Precompile
- EIP-7642: eth/69
- EIP-7910: eth_config RPC Method
- Remove Account Balances & Receipts
- Discovery protocol now uses
basev0
Proof system
Section titled “Proof system”Azul introduces the components that make multi-proof withdrawals possible. The Azul proof system page covers the design in full — the AggregateVerifier dispute game, the TEE and ZK proof paths, and the finality windows. The individual roles are documented separately:
- Azul proof system — AggregateVerifier, finality model, and why the proof system changed
- Proposer
- Challenger
- TEE provers
- ZK provers
- Prover registrar
- Proof contracts