Ethereum's Glamsterdam Is Its Biggest Fork Since the Merge

Ethereum is preparing its most consequential upgrade since the 2022 Merge. Glamsterdam, which reached its final devnet stage on June 16, 2026 and targets a mainnet activation in the second half of the year, bundles ten changes led by two heavy hitters: enshrined Proposer-Builder Separation (EIP-7732) to pull block-building out of trusted middlemen, and Block-Level Access Lists (EIP-7928) to let nodes finally process transactions in parallel. A core developer called it probably the largest fork since the Merge, and the reason is structural: it changes how blocks are built and executed, not just how much they cost.

• Glamsterdam ships around ten EIPs under meta EIP-7773, with two headliners doing the structural work; it hit final devnets on June 16, 2026.
• EIP-7732 (ePBS) moves proposer-builder separation into the protocol, reducing reliance on external MEV-Boost relays that build 80 to 90% of blocks today.
• EIP-7928 (Block-Level Access Lists) maps which accounts and slots a block touches, enabling parallel transaction validation instead of one-at-a-time.
• Together they clear the path to a 200M gas-limit target, roughly tripling the current ~60M, though validators raise it gradually via gas voting.

What is Glamsterdam?

Glamsterdam is Ethereum's next coordinated hard fork and the successor to Fusaka. The name fuses its two halves: Gloas covers consensus-layer changes and Amsterdam covers execution-layer changes, shipped together as one upgrade. It bundles about ten EIPs tracked under meta EIP-7773, but two carry the weight. The upgrade reached its final devnet stage on June 16, 2026, the last major engineering phase before client releases, security review, and public testnets. Mainnet is targeted for the second half of 2026, with developers already naming the fork after it, Hegota, a sign of how far ahead the roadmap now runs.

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Why does ePBS matter for decentralization?

Because it removes a trusted middleman that quietly sits at Ethereum's core. Today, 80 to 90% of Ethereum blocks are built by external relay networks like MEV-Boost: validators outsource the job of assembling a profitable block to third parties and trust them to play fair. That works, but it concentrates power and introduces trust assumptions the protocol was designed to avoid. EIP-7732 enshrines proposer-builder separation directly in the protocol, keeping the useful division of labor while eliminating the external relay, which reduces MEV-related centralization and makes block production more transparent. It also widens the data-propagation window from roughly two seconds to about nine, and that extra headroom is what lets the network safely raise the gas limit later without forcing validators to rush.

How do Block-Level Access Lists speed Ethereum up?

By breaking the single-lane bottleneck. Ethereum executes transactions sequentially because a node cannot know in advance which parts of state a block will touch, so it cannot safely run transactions side by side. EIP-7928 fixes that by including a Block-Level Access List in every block, a map of exactly which accounts and storage slots the block reads and writes, plus the resulting values. Nodes get that map upfront, so they can fetch state and validate non-conflicting transactions in parallel across multiple CPU cores, a multi-lane highway instead of one lane. This is the change that unlocks meaningful layer-1 throughput growth rather than just cheaper blobs, and it is the groundwork for the 200M gas target.

When does it actually ship, and what should holders do?

Not on a locked date yet. Glamsterdam hit final devnets on June 16, and the next stage is public testnets, which is where client teams set the real activation slot. Given that recent forks needed two to four months of testnet seasoning, a September-to-December 2026 window is the firmer base case, and developers caution that Glamsterdam is proving trickier and slower than Fusaka, so slippage is possible. For ordinary ETH holders, the action is none: nothing to do. Stakers and node operators, though, must update both consensus and execution clients before activation, and validators should prepare for the new Payload Timeliness Committee duty ePBS introduces. One scope note: FOCIL was moved out to the following fork to avoid combining too many untested interactions at once.

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1. 2022The Merge. Ethereum moves to proof of stake, the last fork of this structural scale.
2. PriorFusaka ships. The upgrade Glamsterdam directly succeeds.
3. Jun 16 2026Glamsterdam reaches final devnet. All planned EIPs bundled before public testnets.
4. Jul to Aug 2026Public testnet deployment. Client teams use this phase to set the mainnet slot.
5. H2 2026Targeted mainnet activation. Base case roughly September to December; slippage possible.
6. AfterHegota. Next fork, carrying FOCIL and account-abstraction work.

Our take

Glamsterdam is the upgrade that reminds you Ethereum is still willing to change its own engine, not just tune the dials. ePBS and Block-Level Access Lists attack the two most stubborn problems the chain has, trust concentration in block building and the single-threaded execution ceiling, and doing both in one fork is genuinely ambitious, which is exactly why it keeps slipping. That caution is the right instinct: this touches consensus and execution at the same time, and rushing it would be far worse than shipping it in Q4. Holders have nothing to do, but the stakes are high, because if BALs deliver real parallel execution and ePBS actually weans validators off MEV-Boost, Ethereum comes out both faster and more decentralized, a combination its critics say is impossible. Watch the testnets, not the price. The date will move; the direction is what matters.

Original analysis by GenZTech. Figures current as of July 2026. Source: eips.ethereum.org