Solana doubled its targeted block-production frequency by activating 200-millisecond slots on mainnet on Oct. 9. The upgrade halves Solana's original 400-millisecond slot target, creating five block-production opportunities per second instead of 2.5. The change also shortens a network epoch to approximately 24 hours from 48 hours. Anza, the developer behind Solana's Agave validator client, confirmed completion of the SIMD-0525 upgrade.
The activation completes a months-long, four-stage rollout that began in August with a reduction of the slot target to 350 milliseconds. Subsequent reductions to 300 milliseconds and 250 milliseconds prepared validators for Friday's final adjustment. Sampling of Solana's public mainnet RPC showed an average of approximately 222 milliseconds across 1,413 slots following activation. The average compared with roughly 268 milliseconds under the previous 250-millisecond target. Early performance data indicated faster slots, although the network had not consistently reached the new target.
Shorter slot intervals could improve transaction responsiveness for applications operating on Solana. Decentralized trading platforms and market makers particularly depend on rapid updates to prices and orders. Under the SIMD-0525 proposal, each validator's nominal four-slot block-production window has fallen to 800 milliseconds from the original 1.6 seconds. The shorter window reduces how long individual validators can control transaction inclusion. However, the upgrade does not automatically double Solana's transaction-processing capacity. Developers proportionally reduced the computational budget within each slot, keeping the network's approximate execution capacity per second unchanged.
The Solana Foundation said transaction blockhashes now have an expiration window of approximately 30 seconds, compared with 60 seconds under the original configuration. Applications using offline signing or delayed transaction submission therefore have less time before transactions require refreshing. Infrastructure providers must accommodate more frequent blocks. Validators face tighter deadlines for producing and propagating blocks. These demands make sustained performance and skipped-slot rates important measures of the upgrade's success.
Jacob Creech, the Solana Foundation's vice president of technology, said Solana continues to improve with successive software releases. Creech described Solana as the best place to build and identified Alpenglow as the network's next major upgrade. Community attention is shifting to Alpenglow, Solana's planned consensus overhaul. Alpenglow targets transaction finality of approximately 150 milliseconds, compared with roughly 12.8 seconds under the existing TowerBFT system. Alpenglow has undergone deployment on Solana's testnet and devnet. A mainnet activation date has not been announced.