# Soldøgn Interop Milestones ☀️

## Context

**The purpose of Soldøgn is to harden Glamsterdam implementations to maximally scale Ethereum without compromising on its security.**

By bringing together the various client, testing, and research teams involved in Glamsterdam, we can accelerate progress on stabilizing ePBS, finalizing repricing numbers, and agreeing on a post-Glamsterdam gas limit target.

With hindsight, past interop events like [Amphora 🏺](https://blog.ethereum.org/2021/10/15/amphora-merge-milestone), [Edelweiss 🏔️](https://blog.ethereum.org/2023/02/07/edelweiss-interop-recap), [Nyota ✨](https://blog.ethereum.org/2024/05/22/nyota-interop-recap) and [Berlinterop](https://blog.ethereum.org/2025/06/19/checkpoint-4) enabled us to ship each of The Merge, Shapella, Dencun, Pectra and Fusaka much earlier earlier than we otherwise would have. ***At their best, these events give us over 1 month of "async progress time" per day!***

---

## Week Goal

**By end of day Friday, `glamsterdam-devnet-1` running with:**

1. **Stable ePBS implementations**, per [Barnabas's ePBS testing milestones](https://notes.ethereum.org/@bbusa/epbs-testing)
2. **Final repricing numbers** based on the week's BAL and client optimization benchmarks
3. **An X00M gas limit floor** that we believe is a conservative floor for the post-Glamsterdam increase

---

## Feature Tracks

Glamsterdam has two core technical tracks:

| Track | Scope |
|---|---|
| **ePBS** | Evolution of `epbs-devnet-0`; stability and core test scenarios per [Barnabas's ePBS testing milestones](https://notes.ethereum.org/@bbusa/epbs-testing) |
| **BAL + Repricings** | Evolution of `bal-devnet-4`; EL client optimizations (prefetching, caching, parallel I/O); EIP-7904/8037/8038 final gas cost numbers informed by cross-client benchmarking |

**How the tracks converge:** `glamsterdam-devnet-0` merges ePBS with the `bal-devnet-4` spec. `glamsterdam-devnet-1` adds the final repricing numbers from the week's benchmarking work.

---

## Daily Goals

---

### Monday — `glamsterdam-devnet-0` stable

**Target: 4x4 stable glamsterdam-devnet-0,  EIP-8037 spec finalized**

| Track | Monday Goal |
|---|---|
| **ePBS** | Additional CL clients onboarded onto `glamsterdam-devnet-0` |
| **BAL + Repricings** | Benchmarking infra moved to `bal-devnet-3`; client teams begin optimization work, finalize 8037 spec |
| **Combined** | `glamsterdam-devnet-0` stable with 4x4 client coverage; minority clients may lag |

---

### Tuesday — Client optimization sprint

**Target: ePBS stress testing, BAL optimizations, `glamsterdam-devnet-1` spec freeze**

| Track | Tuesday Goal |
|---|---|
| **ePBS** | `glamsterdam-devnet-0` stable overnight; stress testing begins |
| **BAL + Repricings** | client teams working on BAL optimizations |
| **Combined** | `glamsterdam-devnet-0` running without critical issues; eth/70 (EIP-7975) implemented and activated across all EL clients on the devnet, `glamsterdam-devnet-1` spec freeze. |

---

### Wednesday — Client optimizations merged

**Target: by end of day, client BAL optimizations are merged onto branches ready for Thursday's data collection**

| Track | Wednesday Goal |
|---|---|
| **ePBS** | `glamsterdam-devnet-0` continues stabilizing; first look at ePBS test scenarios |
| **BAL + Repricings** | Client optimizations merged onto branches; optimized branches handed off to benchmarking team for Thursday's data collection, test suite release |
| **Combined** | `glamsterdam-devnet-0` stable |

---

### Thursday — Data collection on optimized branches

**Target: `glamsterdam-devnet-1` launch, data collection on optimized branches**

| Track | Thursday Goal |
|---|---|
| **ePBS** | Progress through ePBS test scenarios; stability data collected |
| **BAL + Repricings** | Full data collection run across all clients on optimized branches — both compute and state access benchmarks |
| **Combined** | `glamsterdam-devnet-1` launched with subset of clients |

---

### Friday — `glamsterdam-devnet-1` + gas limit target

**Target: all clients running glamsterdam-devnet-1, stable ePBS, post-glam gas target**

| Track | Friday Goal |
|---|---|
| **ePBS** | ePBS running stably on `glamsterdam-devnet-1` per Barnabas's testing milestones |
| **BAL + Repricings** | Analysis of Thursday's data complete; final repricing numbers for EIP-7904, EIP-8037, EIP-8038 locked; all EIPs ready to include in `glamsterdam-devnet-2` |
| **Combined** | `glamsterdam-devnet-1` finalizing at ~80%+ participation with all client pairs; **all-client sign-off on post-Glamsterdam gas limit target** |

The gas limit target is the headline external deliverable of the week. We'd rather leave with a lower number that every client team is 100% confident in than a higher number with any pushback — "underpromise, overdeliver" is the mantra.

**Closing session:** week recap + path to Glamsterdam on mainnet 🚢

---