Solana Sets Major Upgrade Timeline With Transaction V1 and Alpenglow

Solana targets Transaction V1 for September 9 and Alpenglow for October, alongside rent cuts and faster slot times on the network roadmap.

• Transaction V1 will expand Solana’s transaction size limit to 4,096 bytes on September 9.
• Solana plans five rent reductions that could eventually lower requirements by 90%.
• Alpenglow targets October with approximately 150-millisecond transaction finality.

Solana has outlined a major upgrade schedule, with Transaction V1 set for September 9 and Alpenglow targeted for October. The network is preparing several protocol changes that could expand transaction capacity, lower development costs, and accelerate finality. However, each upgrade follows a separate activation process and timeline.

Transaction V1 Expands Solana Transaction Capacity

Solana’s Transaction V1 upgrade is scheduled to activate on September 9, according to Jacob Creech, Solana Foundation Vice President of Technology. The update will increase the maximum serialized transaction size from the existing 1,232 bytes to 4,096 bytes, representing roughly a 3.3-fold increase.

Consequently, developers will gain more room for complex onchain operations and data-heavy applications. Potential use cases include zero-knowledge proofs, multisignature instructions, BLS signatures, and cross-chain transactions.

However, Transaction V1 will not replace existing transaction formats. Legacy and version-zero transactions will remain valid, while applications must explicitly choose the larger format when required.

Meanwhile, Solana plans to begin its first rent-reduction stage during the week starting August 31. The network has outlined five stages that could eventually reduce rent requirements by 90%, from 6,960 to 696 lamports per byte. Creech outlined the rent schedule on X.

There are a lot of major changes happening soon

– Next week: First step down in rent reduction
– Sept 9: Transaction V1 goes live
– Dropping slot time even further
– October: Alpenglow

Then we all meetup at Scale or Die in November

Solana development will never be the same

— Jacob Creech (@jacobvcreech) August 29, 2026

Lower rent requirements could reduce the SOL developers need to lock when creating accounts and maintaining application state. Therefore, the change could make deploying applications with large numbers of accounts less capital-intensive.

Alpenglow Targets October as Solana Speeds Up

Solana has also reduced its target slot time to 350 milliseconds from 400 milliseconds. Further reductions to 300, 250, and eventually 200 milliseconds remain planned, although specific activation dates have not been announced.

These changes are separate from Transaction V1 and will require individual validator activations. This approach allows network operators to evaluate performance before adopting faster slot targets across the Solana network.

Meanwhile, Alpenglow remains targeted for October. The consensus redesign seeks to replace Solana’s existing consensus architecture while targeting transaction finality of approximately 150 milliseconds.

The upgrade therefore represents a broader protocol change than Transaction V1. Even so, October remains a target rather than a guaranteed mainnet activation date, as testing and network support are still necessary.

Overall, the roadmap signals a concentrated period of development for Solana through late 2026. The upgrades could strengthen transaction flexibility, reduce application costs, and improve confirmation performance.