Anza, the core developer, says Alpenglow took over at slot 459,653,000 at about 10 a.m. Eastern and cut transaction finality from about 12.8 seconds to about 150 milliseconds. SOL traded near $108.51, still below its 50-day average.
Solana changed the way its validators agree on the state of the chain on Wednesday morning, and the token barely noticed.
Anza said Alpenglow became active on Solana's main network at slot 459,653,000 at about 14:00 Greenwich time, or 10 a.m. Eastern, retiring TowerBFT, the voting system the network has run since March 2020. "Transactions now become irreversible in about 150 milliseconds, down from 12.8 seconds," Anza said in a release. Anza and Solana's own accounts said on X that Alpenglow was live on the main network. The Solana Foundation had warned that the timing of the epoch containing the switch could drift from its original estimate.
What changed
Consensus is the process by which validators agree which transactions are final. Under the old system, validators recorded their votes as transactions on the chain itself. Alpenglow replaces that with vote certificates exchanged directly between validators, which is why finality can be faster.
The 150-millisecond figure is Anza's claim, and independent measurements are still to come. Those measurements will show whether the design delivers what its developers say outside a test environment.
One mechanical effect is worth knowing. Removing vote transactions from the chain will lower the transactions-per-second counts that dashboards report. That would reflect a change in measurement, not a decline in usage.
The token
SOL traded at $108.51 at 1:46 p.m., up 1.96% from midnight Greenwich time and 1.72% from this morning, still below its 50-day average of $109.45. Bitcoin rose 1.93% and ether 2.75% over the same period. The market has not priced the upgrade as a separate catalyst.
Further upgrades are planned, including a post-quantum effort called Quantumglow, but none has a committed date, according to developers.
Three readings
One reading is that a clean switch removes the main near-term execution risk and strengthens the network's case for payments, tokenized stocks and trading, where speed and certainty are the product.
A second reading is that the headline number is unproven. A developer's own finality figure is not the same as measured finality on a loaded network over weeks.
A third reading is that none of it matters for price. SOL tracked bitcoin and the Nasdaq today, and the token's recent direction has followed fund flows.
What to watch
Independent measurements of finality; validator behavior and any instability in coming days; transaction counts once dashboards adjust for the change in vote handling; flows into spot Solana funds; and whether activity on the network rises. A measured finality figure near 150 milliseconds that holds under heavy use would confirm the upgrade's central claim.