--- title: "Ethereum Schedules Glamsterdam Upgrade for Sepolia Testnet on October 6" description: "The upcoming network upgrade combines the Amsterdam and Gloas forks, introducing enshrined proposer-builder separation and block-level access lists to scale Layer 1 execution." url: https://basisdesk.news/analysis/ethereum-glamsterdam-upgrade-sepolia-testnet published: 2026-09-30T14:09:06.869Z modified: 2026-09-30T14:09:06.869Z section: Ethereum & L2s author: Basis Desk Newsroom (AI-generated, source-verified) sentiment: neutral tickers: [ETH] tags: [glamsterdam, testnet, epbs, scaling, geth] license: Quote with attribution to Basis Desk (basisdesk.news). Not financial advice. --- # Ethereum Schedules Glamsterdam Upgrade for Sepolia Testnet on October 6 The upcoming network upgrade combines the Amsterdam and Gloas forks, introducing enshrined proposer-builder separation and block-level access lists to scale Layer 1 execution. ## Key points - The Glamsterdam upgrade will activate on the Sepolia testnet on October 6, 2026, combining the Amsterdam and Gloas upgrades. - EIP-7732 introduces enshrined proposer-builder separation to handle payments and block production natively within the consensus protocol. - EIP-7928 introduces block-level access lists to enable parallel transaction validation and more efficient state root computation. ## Editorial remark - **Context:** Ethereum's scaling roadmap has heavily relied on external middleware like MEV-Boost to separate block proposers from builders. Glamsterdam aims to bring this separation directly into the consensus layer while introducing parallel execution primitives to boost Layer 1 throughput. - **Impact:** Node operators must upgrade both consensus and execution clients before October 6, 2026. Developers must audit smart contracts for gas repricing under EIP-8037 and EIP-8038, as fixed gas assumptions or hardcoded limits may cause transaction failures. - **Watch:** The next major milestone is the Sepolia activation on October 6, 2026, at 13:53:36 UTC, followed by the announcement of activation dates for the Hoodi testnet and the Ethereum mainnet. The Ethereum Foundation has scheduled the Glamsterdam network upgrade to activate on the Sepolia testnet on October 6, 2026 [1]. The transition will occur at epoch 353,024, slot 11,296,768, precisely at 13:53:36 UTC [1]. This upgrade represents a major step forward in Ethereum's Layer 1 scaling roadmap, following the previous Fusaka upgrade [1]. Glamsterdam combines the Amsterdam execution layer upgrade with the Gloas consensus layer upgrade [1]. At the time of writing, $ETH is trading at $2,705, down 0.7% over the past 24 hours, amid a broader market capitalization of $2.85T. While the Sepolia activation date is locked, the Ethereum Foundation noted that activation dates for the Hoodi testnet and the Ethereum mainnet have not yet been decided [1]. Node operators must update both their execution and consensus layer clients before the Sepolia activation to avoid being split from the upgraded network [1]. ## Enshrined Proposer-Builder Separation and Block-Level Access Lists The core architectural changes in Glamsterdam focus on how blocks are produced, validated, and processed [1]. The first major change is Enshrined Proposer-Builder Separation (ePBS), introduced via EIP-7732 [1]. Currently, the division of labor between block proposers and block builders relies on external, trusted middleware [1]. EIP-7732 integrates this separation directly into Ethereum's consensus protocol [1]. Under this new system, a proposer includes a builder's commitment to an execution payload, and the builder subsequently reveals the actual payload [1]. The protocol itself manages the payment to the proposer, eliminating the need for third-party relayers [1]. Furthermore, ePBS separates consensus validation from execution validation [1]. This structural shift gives validators more time to validate execution payloads [1]. A newly established payload timeliness committee is tasked with attesting to whether the builder revealed the payload and whether the corresponding blob data was available on time [1]. The second major pillar of Glamsterdam is EIP-7928, which introduces enforced block-level access lists (BALs) [1]. These lists record the specific accounts and storage locations accessed during a block, alongside post-transaction state changes [1]. By providing this structured data, BALs allow client software to read state from disk in parallel, validate transactions in parallel, and compute state roots with greater efficiency [1]. Together, ePBS and BALs are designed to scale execution capacity while keeping node validation practical for home operators [1]. ## Gas Repricing and State Growth Controls To address long-term state growth and resource constraints, Glamsterdam introduces significant adjustments to Ethereum's gas accounting [1]. EIP-8037 increases and separately meters the cost of creating state, while EIP-8038 updates state-access costs [1]. Additional changes modify intrinsic transaction gas, calldata floor costs, access lists, and block gas accounting [1]. These changes will directly impact smart contract execution [1]. The Ethereum Foundation has warned application developers to test their contracts and gas estimation models against the new rules [1]. In particular, contracts that rely on fixed gas stipends, hardcoded gas limits, or assumptions about remaining gas may fail or behave unexpectedly [1]. Developers are urged to consult the Glamsterdam repricing impact guide to search for affected contracts and access testing guidance [1]. To support these gas changes, client teams are already updating their transaction selection algorithms [3]. For example, the Go-Ethereum (Geth) team released version 1.17.7, which accounts for both execution and state gas under EIP-8037 when selecting transactions in the miner [3]. Geth v1.17.7 also includes optimizations to encode and hash block-level access lists once in a dedicated pipeline, and to apply BALs after state sync to keep the snap sync v2 pivot moving [3]. ## Developer and Validator Enhancements Beyond the headline scaling features, Glamsterdam packages a variety of developer-focused improvements and consensus-level adjustments [1]. The upgrade introduces ETH transfer logs, a slot-number opcode (SLOTNUM), an increased maximum contract size, a deterministic factory contract, and new stack-manipulation instructions [1]. On the consensus side, the upgrade introduces forward-compatible data structures and excludes slashed validators from proposing blocks [1]. It also increases exit and consolidation churn, which governs how quickly validators can enter or leave the staking pool [1]. For validators, client configuration will require close attention [1]. The Prysm client team noted that its version 7.2.0 supports the Sepolia fork but will default to a 60-million gas limit after activation [1]. Validators who wish to propose blocks with a 200-million gas limit must configure this explicitly using version 2 proposer settings or the keymanager API, as the older command-line flag for suggested gas limits will have no effect after the Gloas upgrade [1]. ## Implications for the Ethereum Ecosystem The transition of Glamsterdam to Sepolia represents a critical testing phase for Ethereum's scaling roadmap [1]. By moving proposer-builder separation into the protocol layer, Ethereum aims to reduce the centralization risks associated with external MEV (Maximal Extractable Value) infrastructure [1]. If successful, ePBS will democratize block production and secure validator revenues without relying on off-chain agreements [1]. Simultaneously, parallel transaction execution enabled by block-level access lists could significantly boost the transaction throughput of Layer 1 [1]. This is crucial as Ethereum faces stiff competition from alternative Layer 1 blockchains that utilize parallel execution environments [1]. However, the aggressive repricing of state creation and access means that developers must actively audit their decentralized applications to prevent broken user experiences when these changes eventually reach the mainnet [1]. ## What to Watch Next Node operators and developers should monitor several key milestones as the Sepolia activation approaches [1]: * **October 6, 2026 (13:53:36 UTC):** The official activation of Glamsterdam on the Sepolia testnet [1]. Operators must ensure both execution and consensus clients are updated before this date [1]. * **Client Releases:** The Ethereum Foundation will continue updating its client release tables as more Sepolia-compatible versions are confirmed [1]. Currently, Geth v1.17.6 and v1.17.7, Prysm v7.2.0, and Teku v26.9.1 are among the confirmed compatible releases [1, 3]. * **Bug Bounty Program:** The Ethereum Bug Bounty Program is active for Glamsterdam specifications [1]. Security researchers can earn rewards for identifying vulnerabilities in client implementations as they are officially released [1]. * **Mainnet Scheduling:** Once client teams analyze the stability of the Sepolia deployment, they will coordinate and announce the activation dates for the Hoodi testnet and the Ethereum mainnet [1]. ## FAQ **When will Glamsterdam activate on the Ethereum mainnet?** The mainnet activation date has not yet been decided. Client teams will announce the mainnet schedule after observing the upgrade's performance on the Sepolia testnet. **What is Enshrined Proposer-Builder Separation (ePBS)?** ePBS (EIP-7732) integrates the separation of block proposers and builders directly into Ethereum's consensus protocol, removing the reliance on external middleware and managing payments natively. **How does Glamsterdam affect smart contract gas costs?** EIP-8037 increases and separately meters the cost of state creation, while EIP-8038 updates state-access costs. Developers must test contracts to ensure they do not fail due to hardcoded gas limits. ## Sources 1. [Glamsterdam Testnet Announcement](https://blog.ethereum.org/en/2026/09/17/glamsterdam-testnet-announcement) — Ethereum Foundation Blog, 2026-09-28 2. [Glamsterdam Testnet Announcement](https://blog.ethereum.org/en/2026/09/17/glamsterdam-testnet-announcement) — blog.ethereum.org, 2026-09-29 3. [Intact Neuro-Coil (v1.17.7)](https://github.com/ethereum/go-ethereum/releases/tag/v1.17.7) — Geth releases, 2026-09-30 --- Basis Desk Newsroom · AI-generated, source-verified · https://basisdesk.news/about/how-we-use-ai