Overview

• Version 30.0 raises the default OP_RETURN data-carrier limit to 100,000 bytes and allows multiple OP_RETURN outputs per transaction for relay and mining.
• Operators can revert to the prior behavior by setting -datacarriersize=83, with the aggregate limit applying across all OP_RETURN outputs in a transaction.
• Reaction is split, with some developers eyeing larger on-chain data for dApps and critics warning about spam, higher costs, and possible legal exposure for hosting illicit content.
• CoinCentral reports growing use of the Knots client to enforce stricter policies, citing BitRef data that 21.48% of Bitcoin nodes run Knots.
• Beyond policy, v30 adds P2P package-relay improvements, stronger orphan/DoS limits, an experimental IPC mining interface, re-enables external signing on Windows, and adjusts default fee-policy settings.