The Solana Foundation puts the start of epoch 1064, when the handover begins, at about 13:20 UTC, or 9:20 a.m. Eastern. Its developers have pointed to about 14:00 UTC for the switch itself. Firedancer validators sit out the migration, and Solana's co-founder has quipped that a simpler design would have shipped in half the time.
Most of the attention on Alpenglow has gone to speed. The rules the Solana Foundation has published for Wednesday's switch say as much about who gets to validate the network, on which software and at what cost.
According to the foundation's English-language upgrade page, epoch 1064 starts at approximately 13:20 UTC on Oct. 21, about 9:20 a.m. Eastern, and the foundation calls that time an estimate. Older translations of the page gave 15:00 UTC. For the first 5,000 slots, about 18 minutes by the foundation's estimate, the old TowerBFT system keeps running. Alpenglow takes control at slot 459,653,000.
That slot may arrive later than the foundation's arithmetic suggests. Anza, the developer behind the main validator software, has pointed to about 14:00 UTC for the switch, and estimates based on the network's observed slot rate put slot 459,653,000 near 14:02 UTC, or about 10:02 a.m. Eastern.
A fee to keep voting
From epoch 1064, each voting validator needs at least 0.8 SOL in its vote account, above the account's rent-exempt minimum, to cover a new validator admission fee. A validator that falls short does not vote or produce blocks in the following epoch.
With SOL at about $106.68 at 4:46 a.m. Eastern, that is roughly $85 per validator. The sum is trivial for a large staking operation. Because it is a flat charge, though, it weighs proportionally more on the smallest operators, and it adds an administrative step that a careless validator could miss in the first epoch.
One software family at the switch
Validators must run version 4.3.2 of Agave, Jito-Solana or Harmonic Salsa. "Firedancer and Frankendancer are not supported during the migration," the foundation says. Firedancer is the independent client that was meant to give Solana software diversity, so the network will cross its most delicate stretch relying on clients from a single codebase. A bug in that family would have no alternative implementation to fall back on.
The path to this point included setbacks. The upgrade's test cluster went through six resets, a failed migration and a rollback before it completed, according to an account by researchers at Galaxy. The foundation notes that the test cluster goes offline regularly because rehearsing the switch requires it. Anatoly Yakovenko, Solana's co-founder, has also needled the design. "Alpenglow would have shipped in half the time if they just changed the vote program to the ag state machine," he wrote in an Oct. 20 reply on X that ended with a smiley face.
A statistic that will fall on purpose
Alpenglow takes validator votes out of blocks, where they have counted as transactions. Transactions-per-second figures on public dashboards will therefore drop after the switch even if users do nothing differently. Investors who track network activity through that metric will need to adjust for the change, or risk reading a measurement shift as a decline in usage.
How to tell whether it worked
There is a precise signal. A network call named getAgGenesisCert returns nothing while TowerBFT is still in charge; a result after slot 459,653,000 means Alpenglow has taken over. Anza has targeted finality of about 150 milliseconds once it does. A second phase, called Rotor, has no date yet.
For the token, the stakes are lopsided. A smooth switch is largely expected and would support the speed argument for trading and payments use. A stall between about 9:20 and 10:15 a.m. Eastern, on a network running one client family, would land on a token that has been trading on fund flows rather than technology news.
What would change the picture
A pause or rollback announced by the foundation or Anza; the share of stake voting in the first Alpenglow epoch; a date for Firedancer's return; and how data providers restate transaction counts. A morning with blocks finalizing normally through about 10:15 a.m. Eastern would answer the execution question; the participation figure for epoch 1065 would answer the fee question.