Ethereum Tests Glamsterdam Ahead of Expected Launch in December

Ethereum is still aiming 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. However, it remains fragile: Glamsterdam has yet to complete any full passage on a stable private devnet, and several bugs need to be fixed before exposing the update to Sepolia. The mainnet is still scheduled for the fourth quarter of 2026, with no confirmed date.

In Brief

• Glamsterdam aims for Sepolia on October 6, but the date remains conditional.
• Devnet-9 has 1,000 validators and still cannot finalize correctly.
• A bug related to EIP-8037 forces execution layer clients to modify their code.

Devnet-9 Still Blocked Before Transition to Sepolia

Glamsterdam was supposed to use devnets to eliminate such problems before reaching public networks. Cointribune had already been following Glamsterdam's entry into its advanced testing phase in the spring.

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

Stefan Starflinger, DevOps engineer at the Ethereum Foundation, believes that this size has mainly highlighted edge cases that passed less easily on smaller configurations.

Devnet-8 had already encountered a more serious problem. A bug could cause the network to freeze when a validator proposed a block sharing the same parent hash as expected in a specific situation. Client teams have since worked on fixes. So it is not Sepolia that is malfunctioning. Glamsterdam has not yet made it there.

EIP-8037 Adds a New Problem to Solve

Another bug directly affects EIP-8037, one of Glamsterdam's important proposals. This EIP modifies the pricing of creating new permanent data on Ethereum. The network wants to increase its capacity without allowing its database to grow at the same rate. EIP-8037 introduces separate accounting for certain costs related to state creation.

Cointribune had already explained why this adjustment matters in the project aimed at significantly increasing Ethereum's execution capacity.

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

Ethereum will therefore take another turn. 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 being the main step retained in the schedule reported this week.

Parithosh Jayanti, who chaired the developers' meeting, did not guarantee October 6. If the next devnet encounters significant problems again, teams will have to reassess the date "on a case-by-case basis." October 6 is therefore indeed a target. Not yet a promise.

Ethereum: Mainnet Still Aimed for Late 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, however, officially appears as the next milestone with the date of October 6.

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

Enrico del Fante from Consensys has notably advocated for a few more weeks before committing to Hoodi. The issues encountered on Devnet-9 make it difficult to maintain a precise schedule.

The stakes go beyond a simple crypto hard fork. Glamsterdam must profoundly change how Ethereum builds and verifies its blocks. Its program includes ePBS, or integrated separation between proposers and builders of blocks, as well as Block-Level Access Lists, designed to prepare for more parallel processing.

The network is already preparing for what comes next. Cointribune recently detailed the planned work after Glamsterdam around Hegotá and privacy. For now, December remains possible. But Ethereum must first achieve something much simpler on paper: a Glamsterdam devnet that finalizes properly. If Devnet-11 succeeds, October 6 will remain within reach. Otherwise, Sepolia may still have to wait.