Updates

Mystique Hard Fork Brings London Upgrades to ETC

Ethereum Classic activates the Mystique hard fork at block 14,525,000, implementing selected London EIPs.

ETC Community
Ethereum Classic Community
3 min read

The Mystique network upgrade has been successfully activated on Ethereum Classic mainnet at block 14,525,000, bringing selected improvements from Ethereum's London hard fork.

What is Mystique?

Mystique continues ETC's practice of carefully adopting beneficial EVM improvements while maintaining network stability and its core principles.

Key Changes

EIP-3529: Reduction in Refunds

Reduces gas refunds for SELFDESTRUCT and SSTORE operations. This change:

  • Removes gas tokens abuse vectors
  • Simplifies gas estimation
  • Improves network predictability

EIP-3541: Reject New Contracts Starting with 0xEF

Reserves the 0xEF byte prefix for future use (EVM Object Format), ensuring forward compatibility.

Why Not EIP-1559?

Ethereum Classic chose not to implement EIP-1559 (the fee burn mechanism) as it would change the monetary policy of ETC. The community decided to maintain the existing fee market.

Upgrade Coordination

Node operators successfully updated their clients before the fork block, ensuring a smooth transition.

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