Ethereum Classic Activated Magneto to Adopt Berlin’s EVM Changes

Ethereum Classic activated its Magneto network upgrade at block 13,189,133 on July 23, 2021, adopting four protocol changes previously introduced through Ethereum’s Berlin upgrade. The hard fork changed how Ethereum Classic clients validated and priced certain transactions, so miners, exchanges and other node operators needed compatible software to remain on the upgraded chain.

The development mattered because Ethereum Classic was preserving compatibility with Ethereum’s execution environment while continuing as a separate proof-of-work network. That compatibility affected whether developers, infrastructure providers and applications could reuse tooling across the two chains. Magneto also addressed the cost of computationally expensive state access, a security concern extending beyond ordinary transaction-fee optimization.

The activation arrived later than the calendar estimate

ECIP-1103, the governing Ethereum Classic Improvement Proposal, selected block 13,189,133 for mainnet activation and originally estimated that the block would arrive on July 21. Ethereum Classic’s official historical record places the actual activation on July 23. The distinction is important: the block number was the protocol trigger, while the calendar date was only an estimate dependent on block production.

KuCoin’s July 23 operational notice projected activation at approximately 20:00 UTC and suspended ETC deposits and withdrawals beginning at 14:00 UTC. That notice verifies how an exchange prepared for the fork, but its projected time should not be mistaken for an independently established activation timestamp. Trading was a separate function from the node upgrade and transfer suspension.

ECIP-1103 identified Core-Geth and Hyperledger Besu as clients capable of supporting Magneto. It said the Mantis client planned to add support eventually but would not do so in time for the fork. Because Magneto introduced rules that were not backward-compatible, nodes running software without the changes risked following a chain that rejected or accepted different transactions.

Four changes aligned Ethereum Classic with Berlin

Magneto incorporated EIP-2565, EIP-2718, EIP-2929 and EIP-2930. EIP-2565 repriced the modular-exponentiation precompile, correcting gas costs for a computational operation used in some cryptographic systems. It did not reduce every Ethereum Classic transaction fee.

EIP-2718 established a typed transaction envelope that could distinguish new transaction formats from legacy transactions. EIP-2930 used that framework to introduce optional access-list transactions, allowing a transaction to identify addresses and storage keys it expected to access.

EIP-2929 introduced a cold-and-warm access model. The first access to an account or storage location during a transaction became more expensive; repeated access to the same item during that transaction was priced more cheaply. The design better reflected the work imposed on a node and made repeated, poorly priced state lookups more costly to an attacker.

These changes had already activated on Ethereum through Berlin on April 15, 2021. Magneto’s stated objective was maximum compatible behavior between the networks, not a merger of their chains, communities or monetary policies.

Security significance and its limits

The Ethereum Foundation had disclosed on May 18 that underpriced state-access operations could support denial-of-service attacks that forced nodes to perform expensive database work. Its Ethereum-specific test environment suggested that Berlin’s protocol changes reduced one tested attack’s efficiency by roughly fivefold. That was a rough benchmark for Ethereum, not a measured performance result for Ethereum Classic, and it should not be transferred directly to ETC.

A November 18 ETC Cooperative board report later confirmed that Magneto activated successfully on July 23 and characterized the upgrade as an important response to a denial-of-service vector that remained relevant to Ethereum Classic. That later assessment clarifies the security rationale; it does not establish that the July 23 fork eliminated every availability risk or produced a measurable adoption increase.

No defensible event-day price effect is asserted. ETC traded continuously across venues, and the reviewed records do not isolate Magneto from broader cryptocurrency-market conditions. What the evidence establishes is narrower: Ethereum Classic changed its production consensus rules at the designated block, improved Berlin-era EVM compatibility and required infrastructure operators to coordinate around the new rules.