Solana Preps for Larger Transaction Sizes Ahead of Mainnet Activation

The Solana Foundation has announced that infrastructure compatibility checks are underway ahead of the activation of larger transaction sizes on its mainnet. The new format, v1, will increase the maximum size of a single transaction from 1,232 bytes to 4,096 bytes. However, the key issue revolves around whether RPC, indexers, gRPC, and fee sponsors can properly read the new format.

The Solana Foundation has deployed Agave 4.2 to the mainnet, but the 'Larger Transaction Sizes' feature is currently in a waiting state as of September 4, 2026. This change is not merely about size expansion, but also includes features such as large multisig and zero-knowledge proofs (ZK proof). In v1, the reliance on the address lookup table used in existing transactions will be reduced, and fee and resource limit information will be moved to a separate setting called transactionConfig.

The reading method of the existing system could pose issues at this point. If indexers and fee sponsors only skim through the ComputeBudget instruction to calculate fees or compute unit limits, they may miss the fee cap of v1 transactions or read it as zero. The Solana Foundation's transaction-v1 example repository explains that v1 messages contain TransactionConfig instead of ComputeBudget instruction.