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The Ethereum Merge upgrade is expected approximately 15th September 2022 once Ethereum network’s Terminal Total Difficulty (TTD) reaches 58750000000000000000000, at Epoch 144896.
Announcement by Vitalik Buterin
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The Merge consists of a sequence of two upgrades – Bellatrix on the Consensus Layer followed by Paris on the Execution Layer.
Bellatrix upgrades - the Beacon Chain to be “Merge aware”, embedding the Beacon Chain with the Merge logic as validators begin diligently monitoring the Proof-of-Work chain to initiate the Merge transition. Bellatrix is activated at Epoch 144896.
Paris Upgrades – Paris is the Merge transition itself, in which Ethereum Mainnet hot-swaps its consensus from Proof-of-Work to the Beacon Chain’s Proof-of-Stake. The Paris upgrade activates at the chosen Terminal Total Difficulty (TTD) 58750000000000000000000
Validators - Anyone can become a validator by depositing (staking) a minimum of 32 ETH into the specific contract. The protocol then randomly selects participants to propose and vote on new blocks. Staked Ether by validators cannot be withdrawn immediately after the Merge upgrade.
EIP 3675 – this EIP deprecates Proof-of-Work (PoW) and supersedes it with the new Proof-of-Stake consensus mechanism (PoS) driven by the beacon chain. Information on the bootstrapping of the new consensus mechanism is documented in EIP-2982. Full specification of the beacon chain can be found in the consensus-specs repository.
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