Mainnet Merge incoming

Yesterday on the Consensus Layer call, client engineers agreed on Mainnet parameters for the Merge — a Bellatrix epoch of 144896 and a Paris TTD of 58750000000000000000000 (tentative). The TTD is based on Proof-of-Work difficulty and is thus a bit hard to estimate precisely. The target date is September 15, 2022, but this estimate might have even a week of error. On this coming week’s All Core Dev call estimates will be re-checked, and the TTD will either be confirmed or a final adjustment will be made to better hit the target date.

Reminder: 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 dilligently monitoring the Proof-of-Work chain to initiate the Merge transition. Bellatrix is activated at the chosen epoch.

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).

️ All hands on deck ️

Stakers, infrastructure providers, users, and community members — this is your warning. The Merge mainnet sequence is engaged. For the next ~5 weeks, stay tuned, watch for updates, remain agile, and be ready for anything. The following is the high level of dates and events expected to unfold:

[2022/08/18] — TTD reassessed and finalized on All Core Devs call
[2022/08/18 to 2022/8/22] — EL and CL teams cut Mainnet software releases
[2022/08/23] — Client resources, EF blog, and other community and infrastructure announcements of final parameters and releases
[2022/09/06 11:34:47am UTC] — Bellatrix Mainnet upgrade
- All stakers must upgrade to EL+CL Merge-ready nodes before this time
- All infrastructure providers, users, and community members should upgrade PoW nodes to EL+CL Merge-ready nodes before this time
[Estimated: 2022/9/15] — Paris Mainnet Merge transition
- All infrastructure providers, users, and community members must upgrade to EL+CL Merge-ready nodes before this time. Plan on configuring systems at least one week in advance and ideally before Bellatrix

Between initial mainnet release announcements and the final Merge transition, users must remain diligent — monitoring client channels, the EF blog, and other public resources for any new information. Specifically, client teams might release final hardened versions of their software in this time frame and, if possible, users should upgrade.

Huge shout-out to the engineers, researchers, and community members that have worked tirelessly, putting countless hours into this. Merge sequence engaged