Solana Raises Maximum Transaction Size to 4,096 Bytes as txv1 Goes Live

Solana activated the txv1 feature gate on mainnet at the start of epoch 1035 on September 15, 2026 at approximately 01:00 UTC, raising the network’s maximum transaction size from 1,232 bytes to 4,096 bytes, according to an official upgrade note published by Solana.

The change is defined in SIMD-0296 and delivered through the v1 transaction format introduced in SIMD-0385.

Solana said the larger envelope is designed to unlock workloads that previously had to be split across several chained transactions, while the existing v0 and legacy formats continue to work unchanged.

What the 4,096-Byte Limit Unlocks Solana framed the increase as a headroom gain rather than a breaking change.