Ethereum researcher Toni Wahrstätter says Glamsterdam is approaching its final stretch. Client teams have a September 29 release target ahead of the Sepolia fork, while a firm mainnet date remains unannounced.
Ethereum’s Glamsterdam upgrade is scheduled for its next major test on Sepolia on October 6. Researcher Toni Wahrstätter said on September 26 that preparations were approaching the final stretch. The immediate focus in Ethereum’s upgrade agenda is now on the client software needed to put the changes into practice, alongside the features themselves.
Wahrstätter highlighted block-level access lists, or BALs. They are designed to help the computers running the network read data more efficiently when validating transactions in a block. He said the work had delivered benefits beyond its initial scaling purpose, including easier tracing and helping nodes catch up after time offline.
“Glamsterdam will be one of the biggest forks we’ve seen”
Toni Wahrstätter’s update on Glamsterdam and block-level access lists
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Parallel validation moves closer to testing
The EIP-7928 specification describes lists containing the accounts and storage accessed during execution, together with post-execution values. Knowing which data will be needed allows nodes to perform disk reads and transaction validation in parallel. The aim is to reduce reliance on working through a block’s workload sequentially.
The speed improvement does not come from skipping checks. Results calculated by a client must match the list supplied with the block; an incorrect list is not accepted as valid. Wahrstätter also pointed to faster, simpler synchronization through snap v2 as part of the preparation.
Writing an Ethereum Improvement Proposal does not complete that process. Different clients must implement the same rules and work together. Sepolia provides a broader test environment for that compatibility before the changes reach mainnet.
September 29 comes first for client teams
The September 21 developer meeting record lists October 6 for Sepolia and September 29 as the target for client releases. Preparations were discussed again on the September 24 AllCoreDevs call. The schedule therefore predates Wahrstätter’s latest assessment: it is a test plan teams are preparing to execute, rather than a new date proposed in his post.
The first five minutes of the meeting recording, published on Ethereum’s own channel, cover the Sepolia schedule and client release preparations:
The official Glamsterdam page points to the fourth quarter of 2026 for mainnet, without confirming a day. For Sepolia node operators, the immediate task is to track compatible execution and consensus client releases. Mainnet activation will require its own announcement.
No ETH conversion is required. The upgrade does not require holders to exchange their ETH for a new token. Updating client software is preparation for network operators; ordinary holders are not being asked to send their assets to another address.
For the market, a capacity target is not a price forecast. The ETH price is a separate market measure, and the test schedule alone supplies no direction. The longer-term question for Ethereum’s network economics is how technical gains translate into usage and demand for ETH. The next concrete milestones are compatible releases and the outcome of the Sepolia fork.
