Solana to Activate Biggest Mainnet Upgrade in Network’s History on October 21

• Solana will launch Alpenglow on mainnet on October 21.
• Block finality will be reduced from 12.8 seconds to 150 ms.
• For the network, this upgrade will be the biggest in its history.

The Anza team, which develops client software for Solana, announced that the Alpenglow consensus protocol upgrade will go live on the main network on October 21, 2026, at around 14:50 UTC (17:50 Kyiv time). 

The upgrade is expected to cut block finality time from about 12.8 seconds to 150 milliseconds, making transaction confirmations nearly instantaneous. This is the biggest change to Solana’s consensus mechanism since the network launched.

“18 months of work for a migration that happens in one slot,” Anza noted in announcing the launch.

How Alpenglow Will Change How Solana Works

Alpenglow will completely replace TowerBFT — the consensus protocol Solana has used since day one. Consensus allows validators to agree on the order of transactions and determine when a block can no longer be reverted.

In the current system, validators send votes as transactions, and a block is finalized after enough votes have accumulated over 32 slots. Alpenglow changes this mechanism: validators will exchange votes directly and bundle them into certificates. As a result, a block will be able to finalize in one to two voting rounds.

Key features of the upgrade include:

• Finality in 150 ms — instead of about 12.8 seconds, transaction confirmations will take fractions of a second
• Higher throughput — moving validator voting off-chain will free up space for user transactions
• Fault tolerance — the protocol is designed to operate even if up to 40% of the network’s stake becomes unavailable
• Backward compatibility — the Solana virtual machine, transactions, programs, and fees will remain unchanged

According to the Solana Foundation, activation will take place in epoch 1064.

From Testing to Mainnet Launch

The Alpenglow project was unveiled in May 2025. At the time, Solana co-founder Anatoly Yakovenko called it the best thing to happen to the network, emphasizing the importance of maximizing throughput efficiency and achieving single-round finality.

In May 2026, the Anza team reported the first deployment of the new consensus mechanism on the community test cluster. At the time, developers expected a mainnet launch in the following quarter.

The upgrade also drew attention from market participants. Back in September 2025, MEXC Research chief analyst Shawn Yang linked SOL’s potential rise to $215 in September and $250 by year-end to staking, institutional demand, and Alpenglow’s prospects.

Сообщение Solana to Activate Biggest Mainnet Upgrade in Network’s History on October 21 появились сначала на INCRYPTED.