This page lists Solana's protocol changes of 2025 and 2026 in date order, then pending work. Activation dates come from the feature gate accounts on mainnet, read on 2 October 2026 1. Live means the feature is active on mainnet. Approved means it passed a validator vote or was merged into the SIMD repository but is not active on mainnet. Proposed means a published design or an open SIMD.
2025
- 12 February: SIMD-0096 began paying the whole priority fee to the block producer. Live 1.
- 10 April and 23 July: the block limit rose from 48 million to 50 million and then 60 million compute units, under SIMD-0207 and SIMD-0256. Live 12.
- 2 September: validators approved Alpenglow, SIMD-0326, with 98.27% of votes in favor and 52% of stake voting. The SIMD was merged on 9 September. Approved 34.
- December: the Foundation's Breakpoint recap announced Firedancer, Jump Crypto's independent client, officially on mainnet. Its hybrid, Frankendancer, had published mainnet releases since 20 September 2024. Live 256.
2026
- 13 May: P-Token, SIMD-0266, replaced the SPL Token program with a rewrite that does the same work with far fewer compute units: 76 for a transfer instead of 4,645, by the Foundation's figures. Live 119.
- 8 and 22 July: BLS keys in vote accounts and the Validator Admission Ticket, both groundwork for Alpenglow, went live 17.
- 29 July: the block limit rose to 100 million compute units per 400 ms slot, 250 million per second, under SIMD-0286; that is 62.5 million per 250 ms slot today. Live 111.
- 4 August: Jump published v1.1.3, the first full Firedancer release tagged for mainnet 6.
- 19 August to 18 September: three slot-time cuts, below. Live.
- 3 and 11 September: the first two of five rent cuts in SIMD-0437 lowered the rent-exempt deposit from 6,960 to 6,333 and then 5,080 lamports per byte. A 165-byte token account now needs 1,488,440 lamports, against 2,039,280 before. Live 189.
- 15 September: the v1 transaction format went live, raising the size limit from 1,232 to 4,096 bytes as SIMD-0296 proposed. Live 110.
The slot-time cuts
SIMD-0525, written at Anza, cuts the target slot from 400 ms to 200 ms in four feature-gated steps. It keeps four-slot leader windows and 432,000-slot epochs, and scales per-slot limits so capacity per second stays the same. Each gate takes effect one epoch after it activates 11. Averages are measured from block times at each epoch boundary 9:
| Target | Gate activated (UTC) | Took effect (UTC) | Measured average |
|---|---|---|---|
| 350 ms | 19 Aug, slot 440,208,000 | 21 Aug 07:45, epoch 1020 | 365 to 367 ms |
| 300 ms | 26 Aug, slot 441,936,000 | 28 Aug 15:25, epoch 1024 | 315 to 317 ms |
| 250 ms | 16 Sep, slot 447,552,000 | 18 Sep 05:06, epoch 1037 | 266 to 268 ms |
In the four epochs before the first cut, at the 400 ms target, the average was 415 to 416 ms 9. A review published by the Solana Foundation on 28 September found the skip rate stable and vote latency higher, most of all in Asia and South America. The 99th-percentile stretch during which one validator held block production fell from about 3 seconds to about 2 12.
What is pending
200 ms. The last SIMD-0525 gate is not active on mainnet; it was activated on testnet on 15 August and on devnet on 24 August 2026 9. At 200 ms a leader window would last 800 ms and an epoch about a day 11. The same review said the higher vote latency suggests caution about a 200 ms target before Alpenglow, and described the remaining debate as "increasingly philosophical and economic, rather than purely technical" 12. Approved.
Alpenglow. Alpenglow replaces Tower BFT and the Proof of History clock with two components 13. Votor handles voting and finality: a block is final after one round of votes if 80% of stake takes part, or after two rounds if only 60% responds, with both paths running at once. Rotor handles data: it keeps Turbine's erasure coding and stake-weighted bandwidth but sends each block through a single layer of relay nodes, cutting network hops 13. Votes become direct messages between validators instead of transactions 12. Anza's simulations put median finality around 150 ms, sometimes 100 ms, against about 8.5 seconds measured on 2 October 2026 913. The protocol is designed to tolerate 20% adversarial stake plus another 20% offline 13. Its prerequisites are live. Its feature gate was activated on testnet on 24 September and on devnet on 25 September 2026, and does not exist on mainnet. Approved, not live 19.
Multiple concurrent leaders. Today one leader decides what enters its blocks and in what order. Anza's July 2025 roadmap named multiple concurrent leaders as a long-term goal: several validators add transactions in the same window, so a transaction one leader censors can be included by another 14. In March 2026 Anza published Constellation, a design for multiple concurrent proposers built to run in front of Alpenglow as a preprocessor. Proposers submit transactions every 50 ms, attesters record what they saw, and the leader must include anything enough attesters saw, without the power to reorder it 15. No SIMD for it appears in the SIMD repository. Proposed 16.
Other public SIMDs.
- Rent, SIMD-0437 steps three to five: the deposit would fall to 2,575, then 1,322, then 696 lamports per byte, one tenth of the old level. The gates are not active. Approved 18.
- Inflation, SIMD-0550: merged in July 2026, it would double the yearly disinflation rate from 15% to 30%. The governance proposal behind it, SGP-0002, was recorded as accepted on 28 August 2026. Its gate is not active. Approved 11720.
- Leader schedule, SIMD-0675: opened on 29 September 2026, it would reorder the schedule so consecutive leaders tend to be geographically close, shortening handovers under Alpenglow without changing anyone's number of leader windows. Proposed 18.
Sources
- Agave feature gates, checked on mainnet 2 October 2026: activation slots and dates
- Solana Foundation, August 2025: 48M to 60M, Jump builds Firedancer
- Solana Status on X, 2 September 2025: Alpenglow vote result
- SIMD-0326 pull request: merged 9 September 2025
- Solana Foundation, Breakpoint 2025 recap: Firedancer on mainnet
- Firedancer releases: release history
- SIMD-0387: BLS keys for Alpenglow votes
- SIMD-0437: the five rent steps
- Solana JSON-RPC, readings of 2 October 2026: epoch block times, rent minimums, test cluster gates, finality
- SIMD-0296: 1,232 to 4,096 bytes
- SIMD-0525: the four steps, one-epoch delay, 200 ms values
- Solana Foundation, "Slot Time Reduction Effects", September 2026: skip rate, vote latency, leadership interval, the quote
- Anza, "Alpenglow: A New Consensus for Solana": Votor, Rotor, finality simulations, resilience
- Anza, "The Internet Capital Markets Roadmap", July 2025: multiple concurrent leaders
- Anza, "Solana Constellation", March 2026: the Constellation design
- SIMD repository: no SIMD for concurrent leaders
- SIMD-0550: doubled disinflation
- SIMD-0675 pull request: geo-aware leader schedule
- Solana Foundation, P-Token upgrade page: transfer cost before and after
- SGP-0002: accepted status