Solana's Alpenglow upgrade went live: What 150ms finality means for SOL

Solana successfully underwent its anticipated Alpenglow upgrade and swapped out its voting system on a live network on Wednesday. 

No outages were reported.

"Alpenglow is now live on Solana mainnet," the network's official account posted on X. Anza CEO Brennan Watt called it "the largest, most ambitious blockchain upgrade since 'The Merge'," referring to Ethereum's 2022 switch to proof of stake.

What Alpenglow changes

Alpenglow replaces TowerBFT, the system Solana validators have used to agree on the state of the network since its 2020 launch. The first component, called Votor, lets validators exchange votes directly with each other instead of recording every vote as a transaction on the blockchain.

The headline number is finality, the point at which a transaction can't be reversed. Under TowerBFT, that took about 12.8 seconds. Alpenglow targets about 150 milliseconds, though actual times depend on network conditions. 

A block can now be finalised in one round of voting if validators holding 80% of staked SOL back it, or two rounds at 60%.

Moving votes off-chain also frees up block space and cuts costs for validators. Vote fees of roughly 1 SOL per epoch, or about once a day, are replaced by a flat 0.8 SOL admission ticket that is burned. Validators approved the proposal behind the change in September 2025, with about 98% of votes in favor.

Ordinary users and SOL holders don't need to do anything. Fees, wallets and apps work as before.

Why Solana's transaction count looks like it collapsed

Solana's dashboards show far fewer transactions. Vote transactions made up the bulk of what Solana dashboards counted as activity. With votes off-chain, reported transactions per second have fallen sharply even though user activity hasn't.

Non-vote transactions held steady through the switch, at about 2,500 per second in the 14:00 UTC hour on Wednesday, compared with about 2,640 a day earlier, according to Solana Compass. 

How the switch went

The migration needed validators holding at least 82% of staked SOL to sign off before Alpenglow could take over. That was the main risk. Validators running Firedancer and Frankendancer, about 15.8% of stake, couldn't take part and had to switch temporarily to Agave-based software.

A tracker had flagged as much as 45% of stake as not ready shortly before the switch.

The threshold was eventually met and the handoff went through without the fallback Anza had built in. Firedancer operators can now move back, as its latest release supports Alpenglow. Frankendancer won't be supported going forward.

Next on the roadmap are Rotora (a faster way to spread blocks across the network) and Quantumglow (a design for signatures that can resist quantum computers). Neither has a release date.

SOL price after the upgrade

SOL took the launch in its stride. The token traded around $108.80 on Wednesday, up about 2.7% over 24 hours. That still leaves it down about 10% for October after a double top near $122. Buyers have defended $100 several times over the past two weeks. At $108, SOL sits about 63% below its January 2025 record near $295.

Institutional demand has cooled. US spot SOL ETFs posted a $2.6 million net outflow on October 20, all from Grayscale's Solana Trust, their 12th straight session of withdrawals, according to SoSoValue data. The funds still hold $1.54 billion in net inflows since launch.

Hotter-than-expected US inflation data last week revived chatter on a Federal Reserve rate hike at the October 27 to 28 meeting, weighing on Bitcoin and the altcoins that tend to follow it.

Can faster finality lift the price?

Upgrades rarely move prices on their own. When Ethereum completed the ‘Merge’ in September 2022, Ether (ETH) fell about 6% on the day as traders sold the news and stocks slid. 

SOL's small launch-day gain is a better start and Alpenglow's payoff is longer term. Near-instant finality makes Solana more competitive for payments, trading and other uses where speed is paramount. 

Cheaper validation could lower the cost of running a validator. Whether that brings buyers back depends on whether developers and institutions put it to use and on the macro picture over the coming weeks.

The next test is whether ETF flows turn positive and whether next week's Fed meeting gives risk assets room to recover.

SOL price: Levels to watch

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