Developers still hope Glamsterdam can reach mainnet before the end of 2026, despite unresolved testing issues.
Ethereum developers have tentatively scheduled the Glamsterdam upgrade for Ethereums Sepolia testnet on October 6 at 13:53 UTC, even as private devnet testing continues to uncover bugs.
The date gives developers a path toward a December mainnet release, but it remains conditional on whether the next testing phase can produce a stable network.
Glamsterdam Date Depends on Devnet Testing
Protocol specialist Christine D. Kim noted in her latest newsletter that developers agreed to the October 6 Sepolia date while acknowledging several caveats, the biggest of which is that Glamsterdam has yet to run successfully on a stable private devnet.
Glamsterdam-Devnet-9 launched on September 1 with 1,000 validator nodes, making it the largest devnet of its kind by node count so far. But the network is not finalizing, meaning too few validators are correctly proposing and attesting to the chain head.
Ethereum Foundation (EF) developer operations engineer Stefan Starflinger said the size of the network exposed problems, noting it “showed that there are still quite a few edge cases and issues” left to address. He added that the previous devnet, Devnet-8, had an even more serious flaw, a bug that could freeze the entire network if a validator proposed a block sharing its parents hash.
Separately, EF researcher Maria Silva flagged a bug tied to EIP-8037, the State Creation Gas Cost Increase, which will require every execution-layer client to update its code.
Because of those fixes, another devnet is coming, and as of this week, the one to watch is Devnet-11, not 10 as originally planned. Parithosh Jayanti, the Ethereum Foundation developer operations engineer who chaired the call, said that if the new devnet fails again, “wed have to take it case by case” on whether October 6 still works.
You may also like:Hoodi and Mainnet Dates Remain Uncertain
Developers have also held off on setting a date for Hoodi, Ethereums second public testnet in the rollout, with Enrico del Fante of Consensys arguing that waiting a few more weeks before committing to Hoodi would be sensible given the problems found on Devnet-9.
The uncertainty extends to the main network. Developers still hope that the upgrade can reach Ethereum mainnet before the end of 2026, but the Sepolia date does not make the outcome more certain, especially since client implementations are not yet considered ready for mainnet.
As CryptoPotato reported previously, Ethereum‘s broader roadmap has penciled in Glamsterdam’s mainnet activation for December 2026, ahead of a separate push toward quantum-resistant infrastructure targeted for 2029.
That plan, tied to the Hegotá upgrade that follows Glamsterdam, points to Ethereum shipping major changes roughly twice a year, a pace it kept last December when Fusaka activated on schedule.