Ethereum is making a transition from proof-of-work to proof-of-stake through a process called The Merge. This transition will first be activated on the Beacon Chain with the Bellatrix upgrade. Once activated, the proof-of-work chain will migrate to proof-of-stake when it reaches a specific Total Difficulty value.
The Bellatrix upgrade is scheduled for epoch 144896 on the Beacon Chain, which is expected to happen at 11:34:47am UTC on Sept 6, 2022. The transition to proof-of-stake will occur when the execution layer reaches a Terminal Total Difficulty (TTD) value of 58750000000000000000000. This is estimated to happen between Sept 10-20, 2022, depending on the proof-of-work hash rate.
The completion of The Merge transition will be marked by a finalized block produced by a Beacon Chain validator. This is expected to happen approximately 2 epochs (or ~13 minutes) after the first post-TTD block is produced.
To ensure a smooth transition, node operators need to update both their consensus layer (CL) and execution layer (EL) clients. It is also important for validators to be mindful of the risks associated with running a majority client on both the CL and EL.
Various client releases have been made available to support The Merge on the Ethereum mainnet. Node operators must run both a CL and EL client to remain on the network. Validators on the Beacon Chain will also need to run an EL client after The Merge.
Detailed specifications for the consensus and execution layers, as well as their interaction, can be found in the provided repositories. Additionally, there is a bug bounty program with increased rewards for vulnerabilities related to The Merge.
For node operators, it is important to follow the instructions provided by their clients for generating and configuring the JWT token for secure communication between the CL and EL clients. Stakers on the Beacon Chain will need to ensure they are running an EL client in addition to their CL client.
The transition to proof-of-stake expands the responsibilities of validators, as they will need to ensure the validity of user transactions and state transitions. Validators will need to pair their beacon node with an EL client to perform these tasks.
Overall, The Merge represents a significant milestone in the evolution of Ethereum’s consensus mechanism.