Solana switched to a new consensus protocol, Alpenglow, on 21 October 2026. Validators retired TowerBFT, the vote-in-blocks consensus Solana had run on since launch, at slot 459,653,000, around 14:00 UTC, according to Decrypt's report of the activation by Anza, the core developer that built Alpenglow into its Agave validator client.
What changed
Under TowerBFT, validators wrote their votes into later blocks, and a block counted as final after about 12.8 seconds. Under Alpenglow, validators send stake-weighted votes directly to each other, and a block can become final in one of two ways:
- One round: when validators with 80% of the stake vote for it, the block is final at once.
- Two rounds: two voting rounds that each need 60% of the stake, which can be quicker when the voting stake sits close together.
Anza puts finality at roughly 150 milliseconds. The design is meant to stay safe with under 20% of the stake acting maliciously and a further 20% offline. If the network goes 10 seconds without finalising a block, validators gradually lengthen block times until messages get through.
The switch was made on the running network, keeping the existing ledger. Validators approved the change in September 2025, voting 98% in favour of SIMD-0236. It went live on Solana's test clusters before mainnet, and Anza confirmed the 21 October date on 13 October, Decrypt reports. Anza CEO Brennan Watt called it "the largest, most ambitious blockchain upgrade since 'The Merge'".
What it means for validators and delegators
Alpenglow does not change how stake is delegated or how staking rewards are paid out. Its effect is on how quickly blocks become final, and on validators' software and voting, which now happens off-chain between validators rather than through vote transactions in blocks.
Work that Anza has named as next, including Rotor (a new way of spreading block data) and leader rotation that takes geography into account, has no committed dates.
Solana on BitBasic
Solana is new on BitBasic. On 7 November 2026, in epoch 1,080, its dashboard shows 663 active validators with 434.78M SOL staked, 0.10% of leader slots skipped so far in the epoch, and 34 validators, holding 0.15% of the stake, not voting. In the last complete epoch, 1,079, 99.8% of slots had a block. Validators and their clients are listed at bitbasic.com/solana.
