Searching for "0x Version 8.9.1 Download" does not currently yield any official news articles or release notes for a software version with that specific number.

Because of its financial nature, downloading and using 0x requires caution.

Unlike traditional DEXs (like Uniswap V2) that hold liquidity in smart contracts, 0x uses an off-chain order relay with on-chain settlement. This architecture allows for gas-efficient trades and "liquidity aggregation," meaning it scans multiple sources to find the user the best possible price.