Solana activated the txv1 feature gate at the start of epoch 1035 on September 15, 2026, at approximately 01:00 UTC, increasing the network’s maximum transaction size from 1,232 bytes to 4,096 bytes. Defined in SIMD-0296 and delivered through the v1 transaction format introduced in SIMD-0385, the change allows workloads such as zero-knowledge proofs, large multisignature operations and batched programs to fit into a single atomic transaction rather than several chained transactions. That can reduce signature costs and confirmations, while v0 and legacy transactions continue operating unchanged. The upgrade is live on mainnet, testnet and devnet, but RPC nodes and Jito-Solana validators must run Agave v4.2.2 or later to properly handle v1 transactions. The increase follows Solana’s earlier expansion of mainnet block capacity to 100 million compute units and reduction of slot time to 350 milliseconds.