Ethereum’s Glamsterdam upgrade has an October 6 date circled on the calendar. The problem is that the network has not yet made it through a full, stable run on a private devnet.
The Ethereum Foundation still lists October 6 at 13:53 UTC as the target for Glamsterdam’s activation on Sepolia, making it the project’s next official milestone. But after another round of testing problems, that date is looking more like a goal than a guarantee.
The trouble surfaced on Glamsterdam-Devnet-9, launched September 1 with 1,000 validator nodes. It is the largest Glamsterdam devnet so far by node count, and it has exposed a basic but critical problem: the network is still struggling to finalize.
Too few validators are proposing and attesting to the same chain head, preventing the network from reaching finality cleanly.
Stefan Starflinger, a DevOps engineer at the Ethereum Foundation, said the larger configuration appears to have exposed edge cases that were harder to trigger on smaller devnets.
That follows a more serious issue on Devnet-8, where a validator proposing a block with the same parent hash as an expected block could cause the network to freeze. Client teams have since been working on fixes.
So far, Sepolia itself is not the problem. Glamsterdam simply has not cleared the testing stage needed to move there.
Ethereum Has Another Bug on Its Glamsterdam To-Do List
One of the latest headaches is tied to EIP-8037, a major part of the upgrade. The proposal changes how Ethereum prices the creation of new permanent data, with the broader goal of increasing capacity without allowing the network’s database to expand at the same pace.
EIP-8037 introduces separate accounting for certain costs associated with state creation. During testing, Ethereum Foundation researcher Maria Silva found an issue connected to the proposal that requires updates across all affected execution-layer clients.
That means another devnet is now in the picture before Sepolia gets its turn.
CryptoPotato reported that Devnet-11 has emerged as the key test to watch, while Devnet-10 is no longer the main milestone in the schedule currently being discussed.
Parithosh Jayanti, who chaired the developers’ meeting, stopped short of guaranteeing October 6. If the next devnet continues to uncover major issues, developers will reassess the timetable “on a case-by-case basis.”
In other words, October 6 is still alive. It is just not locked in.
Ethereum Is Still Aiming for Mainnet in Late 2026
The bigger deadline has not changed. Ethereum.org continues to place Glamsterdam’s mainnet deployment in the fourth quarter of 2026, without naming a specific day.
Before that can happen, Sepolia needs to go smoothly, followed by Hoodi, the second public testnet planned for the rollout. Developers have not committed to a Hoodi date either, with Consensys’ Enrico del Fante arguing for several additional weeks before setting one.
The reason for the caution is straightforward: Glamsterdam is not a routine software patch. It is designed to alter how Ethereum builds and verifies blocks, with major components including ePBS, which brings proposer-builder separation into the protocol, and Block-Level Access Lists intended to support more parallel processing.
That makes testing more than a box-checking exercise. Each devnet is effectively another rehearsal for a network-level redesign that eventually has to work under public scrutiny.
Ethereum is already looking beyond Glamsterdam toward Hegotá and privacy-focused work. But for now, those plans are secondary to a much less glamorous benchmark: getting a Glamsterdam devnet to finalize properly.
December remains possible for mainnet. Whether Ethereum stays on that path may depend on what Devnet-11 does next.