Max transaction size is growing by more than 3x A new transaction format, Transaction V1 (SIMD-0385), activates on testnet at epoch 1025 raising the transaction size limit from 1,232 to 4,096 bytes. Use cases like ZK proofs, large multisigs, BLS signatures, and confidential transfers that required multiple transactions now fit in one atomic operation. In addition to larger max transaction size, Transaction V1 configures transaction resource requests (such as priority fee) in the new V1 header instead of using compute budget instructions. Transaction V1 is opt-in. Legacy (the original format) and V0 (the format that added address lookup tables) remain supported. Existing apps continue working as is, and can adopt V1 on their own timeline. RPC operators: update to v4.2.2 or v4.3.0-beta.3 to serve the larger size.