Ethereum's Glamsterdam upgrade heads to Sepolia testnet on October 6

Ethereum's Glamsterdam network upgrade activates on the Sepolia public testnet on Tuesday, October 6 — the next milestone after devnet testing, with mainnet activation pencilled in for December 2026.
Sepolia is the proving ground where client teams shake out bugs before a mainnet fork, so a smooth activation would keep the December timeline intact.
Developers caution that client implementations may not yet be fully ready — testnet hiccups at this stage are normal, not fatal.
For ether holders and dapp builders, the upgrade is the next chapter in Ethereum's rolling evolution; the December date is the one to watch.


