Ethereum's Glamsterdam upgrade hits the Sepolia testnet on October 6

Ethereum's next upgrade, Glamsterdam, will go live on the Sepolia test network on October 6, 2026, at 13:53:36 UTC. The Ethereum Foundation set the date. It marks the first public trial of changes to raise throughput and cut the cost of using the chain.

That schedule comes from the Foundation's own announcement, posted on its official blog. Sepolia is one of Ethereum's public test networks, where client teams rehearse an upgrade before it touches real money on the main chain. The post pins the fork to a single slot, epoch 353,024, so every node switches at the same moment.

What Glamsterdam changes

Glamsterdam bundles 18 separate code changes. Two carry the weight. The first, known as EIP-7732 or enshrined proposer-builder separation, moves a job that today leans on outside software into Ethereum's core rules. Right now, specialist firms called builders assemble most blocks and hand them to the validators that propose them. A small set of relay services sits in the middle of that trade. The change writes the handoff into the protocol, so the payment between the two sides no longer rests on trusted middlemen. The Foundation says the goal is to cut reliance on that extra layer.

A second headline feature, EIP-7928, adds block-level access lists. Each block will carry a record of the accounts and storage it touches. That record lets software read data and check transactions side by side rather than one after another. In plain terms, it is groundwork for doing more at once.

For background, a plain guide to how Ethereum works covers how the base layer fits together. Glamsterdam does not change how people hold or send ETH. It reworks how blocks get built and checked.

The push toward a 200 million gas limit

Gas is the unit that meters work on Ethereum. A higher gas limit per block means more transactions can fit inside it. Glamsterdam opens the door to a limit of 200 million gas, up from about 60 million today. That is more than three times the current ceiling.

The jump is not automatic. According to client release notes reported by The Crypto Times, the Prysm software will still default to 60 million gas after the fork, and operators who want 200 million must turn it on themselves. Validators are expected to lift the limit in steps, block by block, so nodes are not strained all at once.

Block-level access lists are what make a higher ceiling realistic. By letting machines validate in parallel, they ease the load that extra transactions would add. The gas increase and the parallel checks are built to work together.

Glamsterdam also adjusts how gas is priced. The Foundation says the new pricing tracks the real cost of running code and storing data more closely than the current rules do. Those are the kind of plumbing fixes that rarely make headlines but shape what the network can carry.

Why this is a trial, not a finish line

A test network is not the real one. Sepolia uses worthless test tokens, and a fork that misbehaves there costs nobody their savings. That is the point. Developers want bugs to show up now.

Glamsterdam also carries smaller changes beyond the two headliners. They include new logs for ETH transfers, an opcode that reports the current slot number, a larger maximum contract size, a fixed address for deploying contracts, and fresh instructions for handling data on the stack. The Foundation told node operators to update both their execution and consensus clients before the fork, or risk dropping off the network.

This is the same team behind recent work such as the zkAPI for private payments. Glamsterdam follows Fusaka, the previous upgrade on Ethereum's roadmap, and the Foundation frames it as another step in a plan to scale the base layer. The releases have kept a steady pace through 2026.

What to watch

The first marker is October 6. If the Sepolia fork goes cleanly, attention turns to the next test network, Hoodi, and then to mainnet. Neither has a date. Developers have said they expect the mainnet upgrade in the fourth quarter of 2026, though the Foundation has not committed to one.

A smooth testnet does not guarantee a smooth mainnet. Past Ethereum upgrades have slipped by weeks when late bugs appeared. For now, the plan covers Sepolia and nothing more.