Ethereum's Glamsterdam protocol upgrade has reached the Sepolia testnet, marking a major testing milestone before any future rollout to Hoodi or Ethereum mainnet. The Sepolia activation was scheduled for October 6, 2026 at 13:53:36 UTC, at epoch 353,024 and slot 11,296,768.
For ordinary ETH holders and self-custody wallet users, this is not a mainnet upgrade yet. There is no requirement to migrate ETH, replace a wallet, change a seed phrase or move assets because of the Sepolia activation. The most important changes are currently relevant to Ethereum client teams, validators, infrastructure providers, developers and applications testing against Sepolia.
At a glance
- Network: Ethereum Sepolia testnet
- Upgrade: Glamsterdam, combining Amsterdam execution-layer changes with Gloas consensus-layer changes
- Sepolia activation: October 6, 2026, 13:53:36 UTC
- Major changes: enshrined proposer-builder separation, block-level access lists and revised gas/accounting behavior
- Scaling focus: more efficient block production and validation, with testing around substantially higher execution capacity
- Hoodi activation: not yet finalized
- Ethereum mainnet activation: not yet finalized
- Action for normal ETH holders: none specifically because of the Sepolia fork
If you are new to the network itself, see the Terenval Ethereum glossary. For an explanation of transaction execution costs, see what gas means on Ethereum.
What happened
Glamsterdam moved from development-network testing to a public Sepolia activation. Sepolia is Ethereum's long-running public testnet and is commonly used to test protocol changes, smart contracts, infrastructure and developer tooling before a mainnet release.
The Ethereum Foundation scheduled the Glamsterdam fork for Sepolia at epoch 353,024. The Sepolia network configuration also records the corresponding Amsterdam execution-layer activation time and Gloas fork version.
This matters because a public testnet gives client developers and infrastructure operators a much more realistic environment than isolated development networks. Problems with validator behavior, gas assumptions, builder infrastructure, client compatibility and application tooling can be discovered before a future mainnet deployment is considered.
Glamsterdam is not a single feature. It is a coordinated protocol upgrade containing multiple Ethereum Improvement Proposals, or EIPs.
What is the Glamsterdam upgrade?
The name Glamsterdam combines two upgrade names: Amsterdam for the execution layer and Gloas for the consensus layer.
Its broader goal is to improve how Ethereum creates, validates and executes blocks while preparing Layer 1 for greater throughput. Two of the most important proposals are EIP-7732 and EIP-7928.
EIP-7732: enshrined proposer-builder separation
Enshrined proposer-builder separation, or ePBS, moves proposer-builder separation more directly into the Ethereum protocol.
In simplified terms, block proposing and block building can be handled as distinct responsibilities, with protocol rules coordinating the commitment and later reveal of the execution payload. This is intended to reduce reliance on trusted middleware for the proposer-builder exchange and to give validators more time to validate execution payloads.
For everyday wallet users, ePBS is infrastructure-level protocol work. It does not change the basic rule of self-custody: control of a wallet still depends on control of its private keys or recovery phrase.
EIP-7928: block-level access lists
EIP-7928 introduces block-level access lists, often shortened to BALs. These lists record which accounts and storage locations are accessed during a block, together with relevant state changes.
The goal is to make parts of block processing more explicit and easier to parallelize or optimize. That is important for Ethereum's scaling roadmap because higher throughput requires clients to process larger workloads without making validation impractical.
BALs are therefore not a wallet feature, but they can indirectly support a network capable of handling more activity over time.
What does the 200M gas limit mean?
Sepolia's Glamsterdam testing also includes work around a 200 million gas limit target. A higher block gas limit allows more execution work to fit into a block, but increasing it safely requires clients, networking and state access to keep up.
That is why Glamsterdam combines scaling-related changes instead of treating the gas limit as an isolated parameter. Features such as block-level access lists, revised gas accounting and client performance work are part of the broader effort to increase Layer 1 capacity responsibly.
A 200M gas limit on Sepolia should not be read as a promise that Ethereum mainnet will immediately use the same configuration. Sepolia is a testing environment, and mainnet parameters remain subject to testing and coordination.
Why it matters
Glamsterdam is important because Ethereum's scaling strategy is not limited to Layer 2 networks. Rollups remain a major part of the ecosystem, but Ethereum developers are also working to improve the capacity and efficiency of Layer 1 itself.
Successful public-testnet operation gives developers more evidence about how these changes behave under real network conditions. It can expose edge cases in execution clients, consensus clients, validator software, builder infrastructure and applications that would be much harder to identify from specifications alone.
For developers, this is also a signal to test assumptions about gas usage, block-building flows, logs, opcodes and state access against the upgraded Sepolia environment.
What crypto users should know
For a normal Ethereum mainnet user, the practical message is simple: you do not need to move your ETH or change your wallet because Glamsterdam is active on Sepolia.
Sepolia is a separate test network. A mainnet wallet does not need a new recovery phrase, and a legitimate protocol upgrade does not require users to send funds to a "migration address."
That distinction is especially important because major Ethereum upgrades are often used as a theme for phishing. Be suspicious of messages claiming that you must enter your seed phrase, connect to an unfamiliar website or transfer ETH to "upgrade" a wallet.
If you use the same recovery phrase to derive accounts across multiple networks, the underlying key-management principles still apply. Terenval's explainer on using the same seed for Bitcoin and Ethereum covers why networks can use related recovery material while maintaining different addresses and transaction systems.
For Sepolia node operators and validators, the situation is different. They need client versions that support the Glamsterdam activation. Both execution-layer and consensus-layer software must be compatible with the new fork rules.
For application developers, now is the time to test against Sepolia and review whether any assumptions about gas accounting, block structure, builder interfaces or state access need to change.
Is Glamsterdam live on Ethereum mainnet?
No. The current milestone is the Sepolia testnet activation.
The Ethereum Foundation's published schedule leaves both Hoodi and mainnet activation dates undecided. A separate announcement is expected when those deployments are finalized.
That means users should avoid treating any Sepolia headline as confirmation that Ethereum mainnet has already upgraded.
Does Glamsterdam change Ethereum wallets?
Not directly.
Glamsterdam changes Ethereum protocol behavior at the network and client level. Wallet applications may eventually adapt to new network behavior, gas estimation or developer tooling, but users do not need to replace their wallet or recovery phrase simply because the upgrade is being tested.
Self-custody fundamentals remain the same: protect your seed phrase, verify transaction details and never disclose private keys to anyone claiming to perform a network upgrade.
What happens next?
The next phase is observation and testing.
Ethereum client teams and developers can use Sepolia to monitor how ePBS, block-level access lists, gas changes and other Glamsterdam EIPs behave in a public environment. Results from that testing will inform later decisions around Hoodi and, eventually, mainnet.
Until those dates are officially announced, the safest interpretation is straightforward: Glamsterdam has reached Sepolia, but the mainnet rollout is still a future step.