The Ethereum network continues its evolution toward a more scalable, secure, and sustainable future. One of the key milestones in this journey was the Berlin hard fork, a system-wide upgrade that went live on April 14, 2021, at block 12,244,000. While the event is in the past, understanding its implications remains essential for developers, node operators, and blockchain enthusiasts navigating Ethereum’s ongoing upgrades.
This upgrade introduced four critical Ethereum Improvement Proposals (EIPs)—EIP-2565, EIP-2718, EIP-2929, and EIP-2930—each designed to refine transaction efficiency, enhance network security, and lay the groundwork for future scalability improvements under the broader Ethereum 2.0 roadmap.
What Was the Berlin Hard Fork?
The Berlin upgrade was a scheduled network update aimed at optimizing Ethereum's core functionality. Unlike contentious hard forks that result in chain splits, Berlin was a coordinated consensus change supported by all major client teams. It focused on technical refinements rather than introducing flashy new features.
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Its primary goals included:
- Adjusting gas costs to better reflect computational expenses.
- Introducing flexible transaction formats.
- Preparing the network for upcoming upgrades like London and the full transition to proof-of-stake.
By fine-tuning these underlying mechanics, the Ethereum community ensured smoother operations ahead of more transformative changes.
Key EIPs Introduced in the Berlin Upgrade
EIP-2565: Reduce ModExp Gas Cost
This proposal lowered the gas cost of the modular exponentiation (ModExp) precompile—a cryptographic function used in privacy-preserving technologies like zk-SNARKs. By making it cheaper to perform complex computations off-chain, EIP-2565 supports advanced scaling solutions such as zero-knowledge rollups, which are now central to Ethereum’s Layer 2 strategy.
EIP-2718: Typed Transaction Envelope
EIP-2718 introduced a new transaction format that acts as an "envelope" for future transaction types. This change allows Ethereum to support multiple transaction formats without breaking compatibility. Think of it as upgrading from a one-size-fits-all letter to a standardized mail system that can handle packages, express letters, and digital notifications—all within the same infrastructure.
EIP-2929: Increase Gas Costs for State Access
To mitigate denial-of-service (DoS) risks, EIP-2929 increased the gas cost for certain state-accessing opcodes—like SLOAD, BALANCE, and *CALL—when accessed for the first time in a transaction. This discourages spam attacks that exploit cheap state reads while maintaining efficiency for repeated operations.
EIP-2930: Optional Access Lists
Complementing EIP-2929, this proposal added a new transaction type that includes an access list—a predefined list of addresses and storage keys the transaction intends to interact with. By declaring access upfront, users can avoid unexpected gas spikes caused by EIP-2929’s higher initial costs. This improves predictability and reduces transaction failure rates.
Why These Changes Matter for Developers
For application developers, the Berlin upgrade subtly shifted how transactions behave—especially around gas estimation and compatibility.
One crucial consideration was EIP-155 compliance. After the upgrade, Geth clients began enforcing EIP-155 by default, which protects against replay attacks by binding transactions to specific chains. Transactions not formatted with chain ID support could fail outright.
While some node providers continued supporting legacy formats temporarily, adopting EIP-155-compliant transactions became a best practice—and eventually a necessity.
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Additionally, smart contract interactions required updated gas estimations due to EIP-2929’s changes. Developers had to adjust tooling (like Hardhat or Truffle) and frontends to account for higher base costs on first-time state access.
What Happens If You Don’t Upgrade?
Nodes running outdated client software risked chain divergence. After block 12,244,000, non-upgraded nodes continued following the old rules, effectively placing them on a deprecated version of Ethereum. This meant they could no longer:
- Validate new blocks
- Process incoming transactions
- Interact with decentralized applications (dApps)
In short: isolation from the live network.
Staying current with client releases—such as Geth v1.10.3+, Nethermind v1.10.0+, or Besu v21.1.0+—was essential to remain synchronized.
Best Practices for Handling Ethereum Upgrades
Even though Berlin is complete, its lessons apply to every future hard fork:
- Monitor Official Channels: Follow updates from the Ethereum Foundation and core client teams.
- Test Early on Testnets: Goerli, Rinkeby, and Ropsten received the Berlin upgrade before mainnet—use them to validate your dApp.
- Audit Transaction Formatting: Ensure your wallet or backend generates EIP-155-compliant transactions.
- Update Development Tools: Keep SDKs, libraries, and node software up to date.
- Use Reliable Infrastructure: Relying on managed services eliminates much of the operational burden.
Frequently Asked Questions (FAQ)
✅ What was the purpose of the Berlin hard fork?
The Berlin upgrade optimized gas costs, enhanced transaction flexibility with typed envelopes, improved DoS resistance, and prepared Ethereum for future scalability upgrades.
✅ Did the Berlin fork affect ETH price or token supply?
No. The Berlin hard fork was a protocol-level improvement and did not alter Ether’s supply or introduce inflationary/deflationary mechanisms.
✅ How did EIP-2930 help reduce gas costs?
EIP-2930 allowed transactions to declare access lists in advance, avoiding high initial gas charges under EIP-2929 when accessing storage or accounts for the first time.
✅ Was user action required during the Berlin upgrade?
For most end users and dApp consumers—no. Wallets like MetaMask handled updates automatically. However, node operators needed to upgrade their clients before the fork block.
✅ Is the Berlin upgrade related to Ethereum 2.0?
Yes. While Berlin occurred on the original proof-of-work chain, it contributed to long-term goals like efficiency and scalability that align with Ethereum 2.0’s vision.
✅ Can old transactions still be processed after Berlin?
Legacy transactions without EIP-155 support were gradually phased out. Modern clients now require chain ID inclusion to prevent replay attacks.
Never Worry About Hard Forks Again
Managing node infrastructure through upgrades like Berlin can be complex and time-consuming. Many development teams choose to offload this responsibility to reliable blockchain infrastructure providers.
These platforms ensure seamless transitions during hard forks, perform rigorous testing across client versions, and maintain high availability—so builders can focus on innovation instead of maintenance.
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Whether you're building DeFi protocols, NFT marketplaces, or Web3 applications, leveraging robust backend infrastructure is key to staying resilient through Ethereum’s rapid evolution.
Core Keywords:
Ethereum Berlin hard fork, EIP-2929, EIP-2718, Ethereum Improvement Proposals, blockchain upgrade, gas cost optimization, smart contract development, decentralized applications (dApps)