Ethereum ACDC #187 Sets Glamsterdam Testnet and Hegotá Scope

Ethereum core developers confirmed October 6, 2026, for the Glamsterdam upgrade on the Sepolia testnet during Ethereum ACDC #187 on September 17. They also advanced several proposals for the next Hegotá upgrade and deferred a decision on the controversial EIP-8363 issuance proposal. The 90-minute consensus-layer call began at 14:00 UTC, according to the official Ethereum Project Management agenda.

The meeting also established QUIC as the default networking protocol for Glamsterdam client releases. Meanwhile, MPLEX is set for deprecation after Glamsterdam reaches Ethereum mainnet. Developers tentatively targeted October 27 for the Hoodi testnet fork, subject to the outcome of the Sepolia deployment.

Ethereum ACDC #187 Confirms October 6 Sepolia Fork

The most immediate schedule decision was to set the Sepolia Glamsterdam fork for October 6.

The official Ethereum roadmap currently lists Sepolia as the next Glamsterdam milestone. It also says the mainnet date has not yet been confirmed. Ethereum.org describes Glamsterdam as a protocol upgrade combining execution- and consensus-layer changes. This is intended to support the network’s longer-term scaling roadmap.

Consensus-layer client teams were given September 29 as the deadline for Glamsterdam-compatible releases. However, developers expressed a preference for earlier releases to leave additional time for security reviews and bug-bounty testing. The Hoodi fork was provisionally placed on October 27, with a go/no-go decision expected after the Sepolia fork is assessed during the October 8 All Core Devs meeting.

The sequence gives developers a testnet checkpoint before any final decision on Glamsterdam’s mainnet activation.

Ethereum Moves Glamsterdam Networking Toward QUIC

ACDC #187 also resolved an infrastructure question that has remained on the roadmap. QUIC will become the default networking protocol for all clients in the Glamsterdam release.

MPLEX will be deprecated after Glamsterdam activates on mainnet rather than being removed immediately. Forkcast’s call record says the relevant specification PR, number 3866, is expected to be merged after the fork.

The distinction matters because a deprecation does not immediately eliminate the older protocol. Client operators therefore have a transition period before MPLEX is fully removed.

The networking decision is separate from the fork’s application-level features. However, it has implications for Ethereum’s ability to move larger amounts of protocol data between nodes. That becomes relevant as developers consider larger execution payloads and other scaling-related changes.

Hegotá Scope Narrows as EIPs Move Through the Process

Developers made several Hegotá decisions during the call.

EIP-8411, which proposes splitting execution payloads into 64 segments for more efficient propagation, received Proposed for Inclusion status. Developers deferred the final Confirm for Inclusion decision while they continue reviewing its implementation and networking implications.

EIP-8015, which removes unused historical deposit and eth1data fields, received Confirm for Inclusion status. The meeting transcript records strong support for the change and describes the affected fields as unused.

EIP-8365, which concerns retirement of legacy 0x00 BLS withdrawal credentials, moved toward inclusion with a narrower scope. Developers agreed to remove forced exits from the current version. The revised approach would prevent new deposits from creating 0x00 validators. It would also postpone forced exits of existing validators to a later upgrade. The EIP author is expected to submit a revised version before the next ACDC call.

Seven proposals were declined for inclusion in Hegotá: EIP-8237, EIP-8341, EIP-8367, EIP-8321, EIP-8243, EIP-8146 and EIP-8375. Developers noted that some of the underlying work, particularly post-quantum research, can continue outside the immediate fork.

The decisions are consistent with the Ethereum Foundation Protocol Cluster’s September 7 assessment of 62 Hegotá proposals. That assessment identified a smaller group of consensus-layer proposals for further consideration and placed several others in the declined-for-inclusion category.

EIP-8363 Issuance Decision Deferred

One of the most closely watched discussions concerned EIP-8363, the Tapered Issuance Burn proposal.

The EIP proposes burning a portion of validator rewards according to the network’s staking ratio, with the burn increasing as the proportion of ETH staked rises. Its stated objective is to prevent Ethereum’s issuance mechanism from continuing to provide an incentive for staking beyond a 50% staking ratio.

ACDC #187 did not approve or reject the proposal.

Instead, developers tabled the issue and agreed that a broader process should be developed before another decision. The transcript-based record says three client teams favored declining the proposal while three abstained. This left developers without a consensus position to make the decision through the ordinary fork-scoping process.

That outcome also matches the Ethereum Foundation Protocol Cluster’s earlier position. Its September 7 Hegotá assessment placed EIP-8363 in the declined-for-inclusion category but explicitly said the decision was not a judgment on the proposal’s merits. The cluster argued that issuance policy affects stakers, ETH holders, and Ethereum’s long-term security budget. Therefore, it warrants broader ecosystem participation.

For readers, the key distinction is that EIP-8363 has not been adopted. However, neither did ACDC #187 settle the underlying issuance debate.

What Happens Next for Ethereum’s Upgrade Roadmap

The next concrete milestone is the October 6 Sepolia Glamsterdam fork. Client teams must prepare compatible releases by September 29, with earlier releases preferred for testing and security review.

Developers will then evaluate the Sepolia deployment before deciding whether to proceed with the provisional October 27 Hoodi schedule. Hegotá work will continue in parallel, including another review of the revised EIP-8365 and further consideration of EIP-8411.

The issuance question will follow a different path. Alex Stokes is expected to propose a process for handling EIP-8363 and similar issuance-related questions with broader community input. This would be different from treating them solely as routine fork-selection decisions.

ACDC #187 therefore produced a clearer near-term testing schedule. However, it left the most economically consequential policy question Ethereum’s future issuance framework open for a wider process.