Solana Alpenglow hits both public testnets with a 150ms finality target
By Node Zero
September 26, 2026
Solana’s Alpenglow upgrade—aimed at cutting transaction finality from about 12.8 seconds to roughly 150 milliseconds—is now active on both of the network’s public test networks, CoinDesk reported early Saturday. Anza announced the devnet switch on September 25, a day after testnet completed its transition, and the Solana Foundation’s upgrade page lists Alpenglow as live on both. The unused Dev Pulse angle is the dual public-network milestone itself—not a reprint of the earlier Agave 4.3 general-adoption file (LN 9507) that only teed Alpenglow up.
Why protocol desks care before any mainnet date. Finality is the point at which a transaction can no longer be reversed. CoinDesk frames the 150 ms target as the wait that could shrink for an exchange releasing deposits or a payment app confirming a merchant sale—color that also matters for NFT marketplaces and GameFi settlement UX once the live chain flips. Attribute the target and the dual-network status to CoinDesk / Anza / Foundation upgrade pages; do not invent that mainnet already runs at 150 ms.
How Alpenglow changes validator agreement. Validators will exchange votes directly instead of recording those votes as transactions inside blocks. Agreement can then take one or two voting rounds. Removing in-block votes will also make some Solana activity charts fall: transaction totals that include validator votes will shrink even if users make just as many payments and trades. The Foundation has told data providers to adjust their comparisons. Services that build transaction histories also need to keep competing candidate blocks separate until the network selects one—mixing their contents could produce an incorrect record. Applications that simply send transactions and read account balances require no migration, per the Foundation’s guide.
What is still simulation, not live proof. CoinDesk stresses the speed figure remains a target derived from simulations, not a demonstrated result under live-market conditions. Wallet processing and exchanges’ own deposit checks can add further waiting time. No firm mainnet launch date has been announced. Anza’s software schedule tentatively allows feature activations to resume September 28, but does not identify that date as Alpenglow’s launch. Stick to that caveat—do not invent a mainnet epoch or a sustained 150 ms live benchmark.
Rejected near-echos for this first Sep 26 OC tick. Bitget’s phased withdrawal calendar (BTC September 28 through other/fiat/P2P October 2) is LN 9755. OpenSea’s 3,000+ theft-linked NFT sell block after Magic Eden / Limit Break is LN 9753. Solana spot ETF’s $86.67M Sep 25 haul is LN 9751. XRPL’s Batch upgrade slip to earliest October 9 is a strong unused alternate—parked for a later tick so this slot takes the dual-testnet Alpenglow milestone. Phygital 59 still lacked a clean last-six-hour primary.
Why Dev & Protocol Pulse 57 plus Latest News 16 plus Editor’s Pick 13 (Sep 26 OC EP day opens at 0/5—this is EP 1/5). Dual public-network Alpenglow activation with a documented 150 ms target and an explicit no-mainnet-date caveat is unused protocol news for the new OC day. Author is Node Zero for desk 57. Publicize stays off.
What not to invent: a mainnet Alpenglow launch date, that live Solana already settles in 150 ms, that September 28 is the activation day, or that every NFT/GameFi client must migrate. Stick to CoinDesk / Anza / Foundation attributions for dual-network status, vote-off-block mechanics, chart-adjustment guidance, and the simulation caveat.
Bottom line: Solana’s Alpenglow upgrade is live on both public test networks with a ~150 ms finality target versus ~12.8 seconds today—and still no firm mainnet date. Unused Dev Pulse news to open Sep 26 OC.
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