Ethereum Glamsterdam Upgrade: ePBS, BALs, and What Is Actually Planned

Ethereum upgrades attract two kinds of noise: confident performance promises and fake instructions telling holders to “upgrade” their ETH. The Ethereum Glamsterdam upgrade deserves a calmer reading. Ethereum.org now expects it on mainnet in Q4 2026 and lists an October 6 Sepolia fork as the next milestone, but the mainnet activation date remains unconfirmed. This article separates the scheduled design from the guarantees and places the upgrade in our broader crypto market news framework.

What Is the Ethereum Glamsterdam Upgrade?

Glamsterdam combines the names Gloas, for the consensus-layer upgrade, and Amsterdam, for the execution-layer upgrade. It follows Fusaka, which activated in December 2025 and introduced PeerDAS for more scalable blob data availability.

The official ethereum.org Glamsterdam roadmap describes three goals: prepare Ethereum for parallel processing, expand capacity by changing how blocks are built and propagated, and control long-term state-database growth. Think of it as remodeling a busy freight terminal. Ethereum is not merely adding another loading bay; it is changing who packs each container, when inspectors receive it, and which inventory records are available before inspection begins.

How ePBS Changes Block Building

Today, many validators use MEV-Boost and third-party relays to receive blocks from specialized builders. This proposer-builder separation exists largely outside Ethereum’s core rules. EIP-7732, called enshrined proposer-builder separation (ePBS), proposes moving the exchange between proposer and builder into the protocol.

Under ePBS, the consensus block and execution payload have separate timing rules. A Payload Timeliness Committee attests to whether the builder released the payload on time, while protocol-enforced payments make the exchange less dependent on trusted relay behavior. Ethereum.org says the design expands the payload propagation window from roughly two seconds to about nine seconds.

That extra time matters because large payloads are harder to broadcast and verify quickly. A wider window can support higher gas limits and more blob data without placing the entire task on the critical path. It does not mean relays instantly disappear: builders and proposers may still use middleware for services beyond the protocol’s basic exchange.

How Block-Level Access Lists Prepare Parallel Processing

Ethereum execution is difficult to parallelize because a client may not know which accounts or storage slots a transaction will touch until it runs the transaction. Two transactions that modify the same state cannot safely be treated like independent jobs.

EIP-7928 proposes block-level access lists (BALs) containing the state accesses and post-execution values associated with a block. The easiest analogy is a warehouse pick map. If workers know which shelves every order will use, unrelated orders can be fetched at the same time; overlapping orders can be scheduled carefully.

BALs can let clients pre-load state, perform parallel disk reads, and identify non-overlapping work. Because the list includes resulting values, it may also support executionless state updates during synchronization. The important distinction is that BALs prepare and accelerate parallel work; they do not by themselves guarantee a specific mainnet transactions-per-second figure.

Gas Repricing: Some Actions Can Get Cheaper While Others Cost More

“Glamsterdam lowers gas” is too broad. The upgrade is considering several repricing changes intended to make gas reflect the hardware and storage burden of each operation more accurately.

For example, the roadmap discusses a lower intrinsic cost for a basic transaction while proposals such as EIP-8037 increase the cost of creating persistent state. The policy logic is straightforward: ordinary transfers can be cheaper, while operations that permanently enlarge Ethereum’s database should pay more of their long-term cost.

Actual fees remain a product of gas used, the protocol’s gas schedule, and demand for blockspace. Even if one transaction type receives a lower fixed gas charge, congestion can still push the market fee higher. For the underlying mechanics, see our Ethereum gas fees guide.

Where the Upgrade Stands on September 17, 2026

The official Glamsterdam roadmap says the upgrade is being tested on devnets, is expected on mainnet in Q4 2026, and has a Sepolia fork planned for October 6. It also says the scope is frozen, while warning that it can still change before mainnet because the governing meta proposal remains in review.

That Glamsterdam meta EIP now lists ePBS, BALs, intrinsic transaction gas changes, state-creation and state-access repricing, validator churn changes, and several smaller execution-layer proposals as scheduled for inclusion. Its activation table still has no epoch or timestamp for Sepolia, Holešky, or mainnet. The practical reading is simple: the feature set is much firmer than it was during early devnets, but October 6 is a testnet milestone and Q4 is a target window—not a confirmed mainnet date.

Client interoperability, testnets, audits, and release readiness still have to converge. Ethereum Foundation protocol leads describe the maturity path as research → EIP → prototype → devnet → progressively firmer inclusion stages → mainnet in their September protocol priorities update. A scheduled EIP is not permission to treat untested behavior or performance estimates as guaranteed.

What Users, Developers, and Validators Should Do

ETH holders

Do nothing solely because of the fork. Your balance does not require conversion. Keep wallet software current through its official channel, ignore unsolicited support messages, and never enter a seed phrase into an “upgrade” page.

Application developers

Watch the final EIP set and re-test gas-sensitive assumptions. Contracts are expected to continue working, but repricing can change deployment and execution economics. Teams that rely on detailed traces or low-level block-building behavior should review client release notes and testnet results rather than infer behavior from headlines.

Validators and node operators

Plan to install supported execution- and consensus-client releases before activation. ePBS changes block-building and attestation flows, so operators should follow their client team’s official release notes and participate in testnets where practical. Do not install binaries linked from social-media replies.

Risks and Limits

• Schedule risk: Q4 2026 is a planning window, not an activation timestamp. Testing can move it.
• Scope risk: the scope is frozen, but the meta EIP remains in review and scheduled proposals can still change before mainnet.
• Implementation risk: a coordinated hard fork touches multiple clients. Interoperability testing reduces, but cannot erase, software and chain-split risk.
• Centralization trade-offs: higher capacity is useful only if ordinary operators can still validate the chain. This is why state growth and propagation time are part of the design discussion.
• Fee uncertainty: repricing does not guarantee every user a fixed percentage reduction. Usage and blockspace demand remain variable.
• Market risk: a protocol upgrade does not guarantee ETH appreciation. Crypto prices are volatile; use only capital you can afford to lose and do your own research.

Frequently Asked Questions

When will Glamsterdam activate?

Ethereum.org currently expects Glamsterdam on mainnet in Q4 2026 and lists the Sepolia fork for October 6. Treat both as planned milestones until client teams publish activation parameters and official protocol announcements confirm them.

Will Glamsterdam make Ethereum process 10,000 TPS?

No official source guarantees that figure. ePBS and BALs are structural changes designed to unlock higher capacity and future parallel execution. Real throughput will depend on the final specification, client performance, gas-limit policy, and workload.

Will every transaction become cheaper?

Not necessarily. Some base transaction costs may fall, while state-creating operations may become more expensive. Network demand will continue to influence the fee paid.

Is ePBS the same as MEV-Boost?

No. MEV-Boost is off-protocol middleware used by many validators today. ePBS places a basic proposer-builder exchange and payment mechanism inside Ethereum’s consensus rules, although optional middleware may remain.

Do I need new ETH after the hard fork?

No. There is no legitimate “Glamsterdam ETH” conversion. Keep your existing keys private and treat conversion requests as scams.

Bottom Line

Glamsterdam is best understood as plumbing for the next phase of Ethereum scaling. ePBS reorganizes block construction, BALs expose state dependencies for faster validation and future parallel execution, and repricing tries to align fees with real resource costs. Those are substantial goals. They are not promises of a fixed TPS number, a universal fee discount, or a market outcome.

Follow the official roadmap and client announcements as the scope matures. This article is educational, not financial advice. Protocol plans can change, crypto assets are volatile, and you should independently verify time-sensitive details before acting. (NFA)