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ETC Network Forks & ECIPs

Ethereum Classic shares Ethereum's pre-DAO history, then diverges. This page maps every fork activation for the networks getc ships with. Values are cross-checked against params/config_etc.go at generation time.

Classic (mainnet, chain ID 61)

ETC's defining choice: it did not apply the DAO fork — the chain that became ETC is the original, unforked one (so DAOForkBlock is nil, which also excludes it from the Fork ID). It runs perpetual PoW: TerminalTotalDifficulty is nil and the chain never merges.

Activation (ETC name) Block Upstream equivalent
Homestead 1,150,000 Homestead
Tangerine Whistle 2,500,000 EIP-150
Spurious Dragon (pt 1) 3,000,000 EIP-155
Gotham 5,000,000 ECIP-1017 era-based issuance
Defuse Difficulty Bomb 5,900,000 ECIP-1041 (ETC-specific)
Atlantis 8,772,000 Byzantium + EIP-158
Agharta 9,573,000 Constantinople + Petersburg
Phoenix 10,500,839 Istanbul
Etchash 11,700,000 ECIP-1099 (60k-epoch DAG)
Magneto 13,189,133 Berlin
Mystique 14,525,000 London without EIP-1559
Spiral 19,250,000 partial Shanghai (no withdrawals)

Not applied: DAO fork, Muir Glacier, Arrow/Gray Glacier, the merge (TTD).

Mordor (testnet, chain ID 63)

Activation (ETC name) Block Upstream equivalent
Homestead … Spurious Dragon 0 active from genesis
Agharta 301,243 Constantinople + Petersburg
Phoenix 999,983 Istanbul
Etchash 2,520,000 ECIP-1099 (60k-epoch DAG)
Magneto 3,985,893 Berlin
Mystique 5,520,000 London without EIP-1559
Spiral 9,957,000 partial Shanghai

ECIP-1017 era length is 2,000,000 blocks on Mordor (5,000,000 on Classic).

ETC-specific rules worth knowing

  • No DAO fork — the original-chain identity of ETC.
  • Mystique = London without EIP-1559 — base fee stays zero; the fork renames IsLondon→IsEIP1559 so London opcodes activate without the fee market.
  • Perpetual PoW — no TTD, no beacon sync.
  • Disinflationary issuance — block reward −20% per era; see ECIP-1017.

Dedicated Files

File Description Changed
params/config_etc.go · diff ClassicChainConfig and MordorChainConfig — all ETC fork blocks and ECIP activations +330 -0
params/config.go · diff ETC chain config fields (ECIP fork blocks, Spiral) +41 -1
params/bootnodes_etc.go · diff ETC and Mordor bootstrap nodes +52 -0

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