Ethereum developers are still aiming to move the Glamsterdam upgrade onto the Sepolia testnet on October 6 at 13:53 UTC, but recent testing problems have made that target less certain. The next key step is now another private development network, after earlier devnets exposed bugs and instability that still need fixes.

The situation is an early test of Ethereum’s push toward a faster upgrade cadence. A mainnet release before the end of 2026, potentially in December, remains possible, but developers have not confirmed a final schedule and say more testing is needed first.

Latest tests exposed multiple issues

The most recent large-scale run, Glamsterdam-Devnet-9, went live on September 1 with 1,000 validators. According to Ethereum Foundation engineer Stefan Starflinger, the devnet’s larger size helped reveal problems, but it is still not finalizing, meaning validators are not consistently reaching agreement on the chain.

Developers also identified a serious issue on Devnet-8. Starflinger said that if a block were created with the same hash as its parent, the network could stop entirely. Another problem was tied to EIP-8037, a proposal that would raise the gas cost of creating new blockchain data. Addressing that issue requires both client software updates and changes to the Glamsterdam specifications.

Focus shifts to Glam-Devnet-11

Because those problems remain unresolved, developers are not moving directly to the next public milestone. Although Devnet-10 had previously been expected to serve as the next major test, attention has shifted to Glam-Devnet-11 instead.

The change reflects a need for a more stable private testing environment before the upgrade is pushed further. Developers chose the tentative October 6 Sepolia date before successfully validating Glamsterdam on a stable devnet, leaving the public testnet schedule dependent on what the next round of testing shows.

Sepolia date is tentative, not fixed

Ethereum Foundation engineer Parithosh Jayanthi had previously indicated that if the next devnet failed, developers would have to judge whether the problems could be fixed quickly enough to preserve the October 6 Sepolia target. That means the date remains provisional rather than guaranteed.

The uncertainty matters beyond Ethereum core development. Layer-2 networks and staking protocols depend on reliable test environments to prepare their own software and integrations before a public testnet activation. If the next devnet remains unstable or uncovers major new issues, developers may decide to delay Sepolia rather than proceed with insufficient testing.

Mainnet hopes remain alive, but timing is unclear

No firm date has been set for Glamsterdam on the Hoodi testnet. Developer comments cited in the source indicate that another public testnet schedule will likely depend on how Sepolia testing progresses, if Sepolia goes ahead as planned.

A December mainnet launch is still viewed as possible, and developers continue to hope the upgrade can reach Ethereum’s main network before year-end. Even so, the current Sepolia target does not guarantee a December deployment, and additional bugs or testing delays could push the release into 2027.

A broader test of Ethereum’s faster release cycle

Developers have framed the current bugs as part of the normal purpose of devnets, which are meant to surface faults before public rollout. In that sense, the issues do not automatically signal failure of the upgrade itself.

The larger question is whether Ethereum can maintain a quicker and more frequent upgrade rhythm without making timelines harder to predict. After Fusaka went live last December and helped Ethereum complete two major upgrades in 2025, Glamsterdam is expected to play a role in keeping that pace in 2026. For now, the next confirmed checkpoint is Glam-Devnet-11, whose results should shape whether Sepolia can still launch on October 6 and whether a December mainnet window remains realistic.

Source: Coin Edition