Solana Alpenglow upgrade gets an Oct. 21 mainnet date

Solana Alpenglow upgrade gets an Oct. 21 date for faster finality

Solana’s Alpenglow consensus upgrade is set to begin in epoch 1064, which starts on Oct. 21 at about 15:00 UTC (11 a.m. ET), the Solana Foundation says.

The Solana Alpenglow upgrade now has a mainnet date. Solana ($SOL) will begin the switch in epoch 1064, which starts on Wednesday, Oct. 21, at about 15:00 UTC, according to the Solana Foundation’s upgrade page.

The quick take

Price: $SOL traded at $105.95, down 0.4% in 24 hours, as of 8:41 a.m. ET on Oct. 14 (CoinGecko).
Trigger: The Solana Foundation set epoch 1064, starting around 15:00 UTC on Oct. 21, for the Alpenglow switch.
Watch: Validators need a client built on Agave 4.3.0 and at least 0.8 SOL in their vote account.

What happened

The foundation’s page says the feature gate turns on as epoch 1064 begins. The network then keeps its current voting system, TowerBFT, for the first 5,000 slots, or about 18 minutes. Alpenglow takes over at slot 459,653,000.

The page treats 15:00 UTC as an estimate, because the start of an epoch shifts with slot timing. CoinDesk reported the new timetable early on Oct. 14, and Decrypt said core developer Anza scheduled the switch for Oct. 21.

Alpenglow replaces TowerBFT, which CoinDesk notes has run Solana’s voting since the network launched in 2020. Today a transaction takes about 12.8 seconds to become final. Alpenglow targets roughly 150 milliseconds.

The foundation calls that figure “an expectation, not a constant.” CoinDesk added that vote transactions will no longer sit in blocks. That could make Solana’s reported transaction count fall sharply, even with no drop in real use.

Validator costs change as well. Voting under TowerBFT costs about 1 SOL per epoch in fees, which Alpenglow removes. Instead, validators must keep at least 0.8 SOL in their vote account for a new admission fee that is charged each epoch and burned.

What to watch next

Supported clients are Agave, Jito-Solana and Harmonic Salsa, each on a release built on Agave 4.3.0. Firedancer and Frankendancer are not supported during the migration, so their operators must switch software for now.

Devnet, Solana’s developer network, turned on Alpenglow on Sept. 25. The foundation advises tracking epoch 1064 rather than the clock. Meanwhile, $SOL is down 9.0% over seven days, CoinGecko data show.

Bottom line: Solana’s biggest change to how it confirms transactions now has a date, but its speed target still has to prove itself on mainnet.