Mainnet Merge Announcement | Ethereum Foundation Blog

Ethereum’s transition to proof-of-stake (The Merge) is imminent, replacing energy-intensive mining with a more sustainable consensus mechanism. Key details include:

Terminal Total Difficulty (TTD): The exact trigger time depends on network hash rate volatility. If miners exit en masse, TTD could be delayed, but an override—like Ropsten’s—is possible.

For Node Operators: Update clients to post-fork versions before the upgrade; failure will strand nodes on a defunct PoW chain.

Validators (Stakers): No stake withdrawals yet—the Merge prioritizes stability over feature additions. Withdrawals are planned in future upgrades, with specs under development for both layers.

Miners: Post-Merge mining will cease entirely. Miners should halt operations once TTD is reached to avoid wasted resources.

Users & Holders: No action required; wallets and exchanges should automatically adapt. Beware of scams exploiting Merge-related confusion.

Developers: Test applications on Goerli (merged) or Sepolia testnets, as deprecated networks like Ropsten will no longer function post-fork. Report issues via the merge-testnets repo for coordinated fixes.

Testnet Deprecation: Only Goerli and Sepolia remain; migrate from Ropsten/Rinkeby/Kiln to these by mid-September.

Community support is available via Merge Community Calls (next on Sept 9, 14:00 UTC) for technical Q&A with developers and ETHStaker members.

The Merge represents years of collaborative effort across researchers, engineers, and testers. Post-upgrade priorities include withdrawals and refining the PoS ecosystem while ensuring stability.

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