Alpenglow: Solana's new consensus

Since 2020, Solana has reached consensus with Proof of History and TowerBFT. On Wednesday, October 21, 2026, around 14:50 UTC, Anza's Alpenglow upgrade replaces TowerBFT on mainnet. It's the biggest change to how Solana agrees on blocks in its history.

What changes

Votor, the new voting protocol. Validators vote directly on blocks with compact signatures. A block is finalized in a single round if 80% of stake votes for it, or in two rounds with 60%. Anza says the design tolerates 20% of stake acting maliciously plus another 20% offline.

Finality in ~150 milliseconds. Today, waiting for full finality takes about 12.8 seconds. Anza expects Alpenglow to bring that to roughly 150ms, depending on how stake is spread geographically. Combined with the 200ms slots that went live in early October, Solana starts to feel like a traditional exchange.

Votes leave the block. Until now, validator votes were ordinary transactions, about 63% of all transactions on the network. Under Alpenglow they move off-chain into certificates. Transaction counts will look lower; that's an accounting change, not a slowdown.

A new validator cost. Instead of paying roughly 1 SOL per epoch in vote fees, validators burn a flat 0.8 SOL per epoch Validator Admission Ticket.

Rotor comes later. Alpenglow's planned replacement for Turbine (block propagation) isn't scheduled yet.

How the switch happens

The feature gate activates at an epoch boundary. A few thousand slots later, validators holding 82% of stake sign a genesis certificate, consensus hands over to Votor, and user transactions resume, which Anza expects to take hundreds of milliseconds. During the migration validators must run an Agave-based client (Agave, Jito-Solana or Harmonic); Firedancer and Frankendancer sit out the switch, and Jump is ending support for Frankendancer.

What it means for you

• Nothing to do. Your wallet, tokens and positions are unaffected. Anyone telling you to "migrate" funds for Alpenglow is running a scam.
• Faster confirmation. Trades, liquidations and payments become final almost instantly, which tightens DeFi markets and makes onchain order books even more competitive.
• A short transition. Expect brief hiccups around the switch; avoid opening large leveraged positions right at 14:50 UTC.

The technical spec is SIMD-0384, written by Anza's Kobi Sliwinski, Ashwin Sekar and Carl Lin. The 200ms slot change is SIMD-0525.