Ethereum's Glamsterdam upgrade is now targeting Q4 2026, a slip from earlier expectations of H1 2026. Developers have launched a new public testnet, Platåberget, to put the upgrade through its paces before it reaches mainnet.
Why Glamsterdam slipped
The timeline shift gives client teams more room to handle the breaking changes Glamsterdam introduces. Applications with hardcoded maximum gas limits will need to adjust, since the upgrade alters how those limits are processed. For teams that baked in a fixed ceiling, this is not a drop-in update.
The Platåberget testnet is now live for Glamsterdam, giving developers a place to test against those changes before the real thing.
What breaks
The core issue is straightforward: any app that hardcodes a maximum gas limit will behave differently after Glamsterdam. That's a niche but real group of contracts, and the kind of thing that tends to surface only after a mainnet upgrade goes through.
Developers have a few months to sort it out. The Q4 target means the testnet window is the main runway for catching edge cases.
The Hegotá lineup
Looking past Glamsterdam, the Hegotá upgrade is expected in 2027. FOCIL (EIP-7805) is confirmed for that fork. Frame Transactions (EIP-8141) is still under consideration, not locked in.
That distinction matters. FOCIL is a consensus-layer change designed to improve censorship resistance, and it's now a definite part of Hegotá. Frame Transactions, which would change how transaction types are structured, remains an open question.
Ethlabs, an independent Ethereum research lab, is pushing for Quick Slots and more L1 capacity. Their advocacy doesn't guarantee anything, but it frames the debate as Ethereum heads into 2027.
The next deadlines
Developers have until Aug. 27 to finalize Hegotá's proposed-for-inclusion list. Client teams then submit their preferences by Sept. 10.
That's a two-week window, and it's where the real decisions get made. The list determines what actually ships in Hegotá, and the Sept. 10 cutoff is the hard stop for client teams to weigh in.
Frame Transactions has a shot at making the cut, but it's not guaranteed. The Aug. 27 deadline will settle that.
