The Ethereum Foundation launched a public testnet called Plataberget on August 17, 2026, giving developers and ordinary users an early place to try the Glamsterdam upgrade before it reaches the main network. The announcement came through the Foundation's blog and was flagged by Cointelegraph the same day. The testnet is scheduled to run the Glamsterdam fork on August 20, simulating the transition on a live chain.
Plataberget sits ahead of the usual staging testnets. After it, Glamsterdam is set to be tested on Sepolia and Hoodi before any mainnet activation. The purpose is straightforward: let wallets, apps, and node operators break things now, on a network where nothing is at stake, rather than after billions of dollars in value depend on the code behaving.
Three changes at the core of Glamsterdam
Glamsterdam bundles several protocol-level changes, and three carry the most weight for how Ethereum blocks get built and priced.
The first is enshrined proposer-builder separation under EIP-7732. Today block building and block proposing already split in practice through outside software, but the roles are not part of the protocol itself. Baking the separation into the base layer is meant to reduce reliance on trusted middleware and change how validators and builders coordinate on each block.
The second is block-level access lists, EIP-7928. These require a block to declare, up front, which accounts and storage slots its transactions will touch. Clients can then read that state in parallel instead of discovering it transaction by transaction, which sets up faster execution and cleaner paths to future scaling work.
The third is a gas repricing. Adjusting the cost of specific operations shifts the economics of running transactions and can move fee pressure around the network. For anyone funding an on-chain balance, including users who top up a card from their own wallet, gas repricing is the part of this upgrade most likely to show up in day-to-day costs. Efficient settlement on Ethereum feeds directly into the stablecoin rails that many spending products now depend on.
Taken together, the Foundation has described Glamsterdam as one of the larger restructurings of Ethereum's underlying machinery, not a routine parameter tweak.
Timeline slipped to Q4 2026
The public test arrives against a moved deadline. Developers pushed the mainnet target for Glamsterdam to the fourth quarter of 2026, from an earlier plan that aimed for the first half of the year. The delay reflects the scope of the changes and the number of test rounds the team wants to complete first.
Several months of testing are planned across Plataberget, Sepolia, and Hoodi. Running an early public network like Plataberget is part of that budget: it widens the pool of people probing the fork and surfaces integration problems that internal devnets can miss. The August 20 fork on Plataberget is the first real checkpoint, a full transition on an active chain rather than a lab simulation.
Testing that reaches ordinary users
Plataberget is public by design, and that matters beyond the core client teams. Wallet developers can confirm their software signs and broadcasts correctly under the new rules. Infrastructure providers can check that indexers and RPC endpoints keep pace with block-level access lists. Users who hold their own keys and interact with contracts directly can watch how the fork behaves before it lands on assets they actually care about, which is the kind of dry run self-custody setups benefit from most.
The staged approach also lowers the odds of a disruptive mainnet activation. Ethereum's recent operational record across its ecosystem, including outages on rival chains, has kept reliability front of mind, and a longer testing window is the direct response.
Overview
The Ethereum Foundation opened Plataberget, a public testnet, on August 17, 2026, and will run the Glamsterdam fork on it on August 20. Glamsterdam brings enshrined proposer-builder separation (EIP-7732), block-level access lists (EIP-7928), and a gas repricing. Mainnet is now targeted for Q4 2026 after slipping from the first half of the year, with Sepolia and Hoodi testing to follow. For now, Glamsterdam is code to be stress-tested in the open, not a live mainnet change.
