Ethereum developers eye October Sepolia test for Glamsterdam upgrade

The core of the apprehension lies in EIP-7732, an Enshrined Proposer-Builder Separation (ePBS) design that shifts the responsibility of transaction payload assembly from validators to specialized builders. During a recent consensus call, developer Potuz warned that because testnet ether lacks the economic value of mainnet assets, attackers could easily spin up thousands of builder identities to win auctions and subsequently withhold transaction payloads. While this would not directly threaten mainnet funds, it could effectively cripple the testnet's availability for infrastructure teams.

To mitigate these risks, developers are weighing the need for more robust circuit breakers capable of identifying and rejecting abusive builder behavior. The schedule remains tight; client teams are urged to finalize software by September 29, leaving only one week for review before the October 6 launch—half the standard duration. While the Sepolia network offers a controlled environment with a permissioned validator set, the compressed timeline reflects a broader effort to move the Glamsterdam roadmap forward. Despite the progress demonstrated by the recent successful Devnet-11 rehearsal, which pushed block gas limits to 200 million, the mainnet activation date for Glamsterdam remains unscheduled, with the target window currently set for the fourth quarter of 2026.