Agave 4.2 Release Overview

Agave 4.2 Release Overview

Updated October 2026 • Solana Foundation

Agave 4.2 is the next release of Anza's Solana validator client, recommended for mainnet adoption in August 2026 with feature activations expected to start the week of August 17, per the v4.2 release schedule. The release carries three feature-gated upgrades: a 90% rent reduction, larger transaction sizes, and reduced slot times. The release also includes the necessary code to run Alpenglow, allowing core developers and validators to test Alpenglow in a community test cluster. Alpenglow was not activated on mainnet in Agave 4.2; after further testing, it activated under Agave 4.3 at epoch 1064 on October 21, 2026.

Technical Details

Reduced Rent

SIMD-0437 cuts lamports_per_byte, the constant behind Solana's fully refundable storage bond, from 6,960 to 696 — a 90% reduction. The cut rolls out across five independent feature gates so core developers can monitor state growth at each step, with a fallback gate that can restore the current value if needed.

This means creating on-chain state gets dramatically cheaper: the rent deposit for a standard SPL token account falls from about $0.159 to $0.0159, making it practical for businesses to cover rent on behalf of their users at scale.

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Larger Transaction Sizes

SIMD-0296 raises the maximum transaction size from 1232 bytes to 4096 bytes, delivered through the new transaction v1 format. Existing v0 and legacy transactions continue to work unchanged; applications opt in by adopting v1.

This means workloads that never fit inside a single transaction, such as ZK proofs, large multisigs, and on-chain signature schemes like BLS, can now land as one atomic transaction instead of being stitched together with lookup tables or bundles. Indexers that decode raw transaction bytes will need to recognize the new transaction v1 layout.

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Reduced Slot Times

SIMD-0525 halved Solana's slot time from 400ms to 200ms, rolled out in four 50ms decrements gated by successive feature activations. Block skip rates gated each step: the network would not advance to the next decrement if they were too high. The final 200ms step took effect at the start of epoch 1053 on October 9, 2026.

This means users see confirmations twice as fast, market makers can quote tighter spreads, and each leader's monopoly over block building narrows — improving both latency and censorship resistance.

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Alpenglow: Feature Complete in 4.2, Live in 4.3

Agave 4.2 contained the code changes for Alpenglow, Solana's new consensus protocol, while core engineers continued testing and hardening the code base. Alpenglow was not activated in 4.2: it activated on mainnet under Agave 4.3, the following release, at epoch 1064 on October 21, 2026.

Alpenglow replaced TowerBFT with the Votor voting algorithm, targeting roughly 150ms finality compared with TowerBFT's 12.8 seconds. It eliminated vote transactions entirely: validators exchange votes directly. Votor tolerates 20% of stake being offline plus 20% of stake being adversarial. Validators running 4.2 already carried the complete Alpenglow code, which set the network up for the consensus migration in 4.3.

Read the full article: Alpenglow

About This Upgrade

Agave 4.2 delivers major improvements across three axes: cheaper on-chain state through the rent reduction, more capable transactions through the 4096-byte v1 format, and lower latency through 200ms slot times. Just as importantly, with Alpenglow feature-complete, the 4.2 release set the stage for the largest protocol change in Solana's history, which went live with Agave 4.3.

Learn more: Solana Upgrades