Solana has launched the Transaction V1 upgrade on its mainnet, which occurred at epoch 1035 on September 15, 2026. This update increases the maximum transaction size from 1,232 bytes to 4,096 bytes, representing a 3.3x expansion.
The technical implementation was guided by Solana Improvement Documents SIMD-0296 and SIMD-0385. The project was led by Anza and coordinated by the Solana Foundation, with contributions from engineers Jacob Creech and Andrew Fitzgerald.
The rollout process included local testing in August 2026 and a testnet launch on September 1 at epoch 1025. The new V1 format is optional for senders, while legacy and V0 formats remain supported to ensure application compatibility.
The increased capacity allows for atomic execution of complex operations, including zero-knowledge proofs, large multisig configurations, and confidential transfers. This reduces the need for multiple on-chain interactions.
Infrastructure providers, such as RPC services and indexers, must update their systems to accommodate the new transaction format. The Solana Foundation noted that these changes affect compute limits and priority fees for wallets and block explorers.
