Ethereum : Bugs Still Threaten Glamsterdam's Schedule

Ethereum still aims for October 6 at 13:53 UTC to activate Glamsterdam on the Sepolia testnet. The date now appears as the next milestone on Ethereum’s official roadmap. But it remains fragile: Glamsterdam has not yet completed any full run on a stable private devnet, and several bugs must be fixed before exposing the update to Sepolia. The mainnet is still planned for the fourth quarter of 2026, with no confirmed date.

Devnet-9 Still Blocks Before Transition to Sepolia

Glamsterdam was supposed to use devnets to eliminate these kinds of problems before reaching public networks.

Five months later, tests are much heavier. Glamsterdam-Devnet-9 was launched on September 1 with 1,000 validator nodes, making it the largest Glamsterdam devnet so far by node count. The result is not yet as expected: the network does not finalize properly. Too few validators propose and attest the same chain head to reach finality.

Stefan Starflinger, DevOps engineer at the Ethereum Foundation, believes that this size mainly highlighted edge cases that were less likely to appear in smaller configurations.

Devnet-8 had already encountered a more serious problem. A bug could freeze the network when a validator proposed a block sharing the same parent hash as the one expected in a specific situation. Client teams have since worked on fixes. So Sepolia is not malfunctioning. Glamsterdam just hasn’t succeeded there yet.

EIP-8037 Adds a New Problem to Solve

Another bug directly affects EIP-8037, one of the major proposals of Glamsterdam. This EIP changes the pricing for creating new permanent data on Ethereum. The network wants to increase capacity without letting its database grow at the same pace. EIP-8037 notably introduces separate accounting for certain costs related to state creation.

Maria Silva, researcher at the Ethereum Foundation, identified during testing a problem related to this EIP. The fix requires updating all affected execution layer clients.

Ethereum will therefore take another round. Developers are now preparing a new devnet before Sepolia. CryptoPotato indicates that Devnet-11 has become the test to watch, with Devnet-10 no longer the main step retained in this week’s reported schedule.

Parithosh Jayanti, who chaired the developers’ meeting, did not guarantee October 6. If the next devnet still encounters significant problems, teams will have to reassess the date “on a case-by-case basis.” So October 6 is definitely a target. Not yet a promise.

Ethereum: Mainnet Still Targeted End 2026, No Confirmed Date

Ethereum.org continues to display Q4 2026 for the deployment of Glamsterdam on the mainnet. No specific day is indicated. Sepolia, meanwhile, officially appears as the next milestone with the date of October 6.

After Sepolia, Hoodi must still come, the second public testnet planned in the deployment. Here too, developers preferred to wait before setting a date.

Enrico del Fante, from Consensys, notably advocated for a few additional weeks before committing on Hoodi. The problems encountered on Devnet-9 make a precise timeline difficult to keep.

The challenge goes beyond a simple crypto hard fork. Glamsterdam must deeply modify how Ethereum builds and verifies its blocks. Its program notably includes ePBS, or built-in separation between block proposers and builders, as well as Block-Level Access Lists, designed to prepare for more parallel processing.

The network is already preparing the next steps. For now, December remains possible. But Ethereum must first achieve something much simpler on paper: a Glamsterdam devnet that finalizes cleanly. If Devnet-11 succeeds, October 6 will remain within reach. Otherwise, Sepolia may still have to wait.