Solana is preparing to activate its Alpenglow upgrade on Wednesday, introducing its biggest network overhaul since 2020. The upgrade will replace the blockchain’s current voting mechanism and target transaction finality of around 150 milliseconds, following months of testing that included an unsuccessful migration and a subsequent rollback.
With the new system, Solana transactions could become irreversible in approximately 150 milliseconds, making finality nearly 40 times faster than the current process. The improvement could accelerate settlement across the network and bring the experience closer to traditional card payments and centralized trading platforms.
Alpenglow redesigns how validators, which process transactions and verify network activity, reach consensus on transaction validity.
Under Solana’s existing system, validators submit votes directly to the blockchain as transactions. Payments become final once enough votes have accumulated, a process that typically takes around six seconds.
The upgraded mechanism will move voting off-chain and consolidate validator votes into certificates. These certificates can establish finality within one or two consensus rounds. If the network reaches its 150-millisecond mainnet target, transactions could be finalized in less time than a blink.
Speed is particularly important in volatile cryptocurrency markets, where prices can shift within seconds. Exchanges and payment applications also rely on confirmation periods before treating deposits as settled.
Bringing finality down to a fraction of a second could strengthen Solana’s competitiveness against centralized trading venues and card payment networks. Ethereum, by comparison, takes roughly 13 minutes to achieve full finality.
Robin Nordnes, founder and CEO of Raiku, which builds trading infrastructure on Solana, said the upgrade could temporarily reduce the network’s reported transaction count.
Nordnes explained in an email that such a decline would not necessarily indicate reduced activity. Many transactions currently counted on the network are validator votes, and moving those votes off-chain could lower the reported total even if trading volumes remain steady.
He added that faster finality would benefit trading firms, although proximity to block production infrastructure remains more important for some trading strategies.
Alpenglow Targets Lower Solana Validator Costs
Beyond improving transaction finality, Alpenglow is designed to reduce the expenses associated with running Solana validators.
Under the current system, validators pay approximately 2 SOL daily in voting fees. These costs doubled after Solana recently reduced slot times, the intervals allocated for block production, to around 200 milliseconds.
The upgrade will eliminate these voting fees and introduce a fixed validator admission ticket costing 0.8 SOL per epoch. Each epoch lasts approximately 24 hours, and the new fee structure is expected to reduce voting expenses by roughly 60%, based on the reported figures.
However, Alpenglow’s development has encountered several technical challenges.
Since testing began in early May, the test network has undergone six full resets. Galaxy Digital, one of roughly 100 validator operators involved in the testing process, reported that an attempted migration to the new system failed network-wide and had to be rolled back.
A later migration succeeded, allowing preparations for the planned Wednesday activation to continue.
The setbacks did not put customer funds at risk because the failures occurred on a test network designed to identify problems before the mainnet rollout.
Activation is scheduled to begin with epoch 1064 on Wednesday. The main transition is expected at slot 459,653,000, following a 5,000-slot transition period.
Falling Validator Numbers Fuel Decentralization Concerns
Alpenglow is arriving as Solana faces a decline in the number of active validators securing the network.
Bitwise’s latest staking report showed that the active validator count dropped to 659 at the end of September, compared with 696 three months earlier. The figure is also around 30% lower than a year ago, despite approximately 69% of SOL’s total supply remaining staked.
Staking participation has also become increasingly concentrated among larger operators.
Data from Solana Compass shows that the minimum number of validators collectively controlling more than one-third of staked SOL fell from 20 to 18 over the past year. Meanwhile, the ten largest validators increased their combined share of staked SOL from 22.2% to 24.5%.
Bitwise linked part of the decline in validator participation to operating costs. By eliminating voting fees, Alpenglow could ease the financial burden on smaller operators and make it more affordable to keep their validators running.
However, lower voting expenses will not remove other operational costs, including hardware, bandwidth and hosting.
Ultimately, Alpenglow aims to deliver faster transaction finality while making validator operations less expensive. Its long-term impact will depend on mainnet performance and whether smaller operators can remain active without further concentrating control of the network.
