Ethereum has confirmed dates for the Glamsterdam upgrade while highlighting a potential testnet threat involving fraudulent block builders, according to CoinDesk. On the Sepolia testnet, free test ether could allow fake builders to bid more aggressively than legitimate competitors and then withhold transaction payloads. The issue may complicate testing and delay progress if malicious participants interfere with block production. At the same time, Ethereum client teams will have half their usual review period before the Sepolia stage, adding pressure to assess implementation changes. The warning comes as developers prepare for the next phase of Glamsterdam, with the testnet environment serving as an important checkpoint for the upgrade. The source did not provide specific dates in the supplied material, but confirmed that a timeline has been set. The developments are directly relevant to Ethereum and ETH, as disruptions during testing could affect the upgrade process rather than current network trading conditions.
