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Solana sets Oct. 21 Alpenglow switch, targeting 150ms finality

Solana’s Alpenglow consensus upgrade is scheduled for Oct. 21 and targets finality in about 150 milliseconds, though the actual result will depend on network conditions.

BitCurrent Newsroom2 min read

Solana sets Oct. 21 Alpenglow switch, targeting 150ms finality

Solana’s validators currently use TowerBFT to agree on transactions, a process that takes about 12.8 seconds to finalize a block. The Solana Foundation says its Alpenglow upgrade is scheduled to activate on mainnet on Oct. 21, targeting finality in roughly 150 milliseconds.

  • Activation: epoch 1064, expected to begin around 13:20 UTC.
  • Target finality: about 150 milliseconds, down from 12.8 seconds.
  • Consensus switch: after the first 5,000 slots of the epoch, about 18 minutes later.

The Foundation’s Alpenglow upgrade page says the protocol replaces TowerBFT’s validator voting layer. The 150-millisecond figure is a target, not a confirmed performance result; actual finality will depend on network conditions, according to CoinDesk’s report.

How will Alpenglow change validator voting?

Under Alpenglow, validators will send votes directly to each other and combine approvals into certificates. A block can then become final after one or two voting rounds, according to the Foundation.

Validator votes will no longer appear as transactions in blocks. That could sharply reduce reported transaction counts even if user activity does not change.

When does the new consensus take over?

The feature is scheduled to activate at the start of epoch 1064, which the Foundation estimates will begin at about 13:20 UTC on Oct. 21. The network will continue running TowerBFT for the first 5,000 slots, with the Alpenglow consensus switch expected roughly 18 minutes into the epoch.

The estimated time may shift with slot timing. The Foundation advises tracking the epoch rather than treating 13:20 UTC as an exact switch time.

What remains open about the upgrade?

The date and mechanism are scheduled; the finality target has yet to be demonstrated on mainnet. Whether transactions reach finality in roughly 150 milliseconds after activation remains to be seen.

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