Bitcoin Core developers are planning changes to OP_RETURN data limits in version 30.
A group of Bitcoin Core developers has set October for the implementation of changes to the management of OP_RETURN outputs — a field that allows small amounts of arbitrary data to be inserted into Bitcoin transactions.
Currently, Bitcoin Core’s default mempool limits these outputs to 83 bytes. The upcoming modification will increase this limit to nearly 4MB per output. Some developers, including Antoine Poinsot and Peter Todd, argue for the need for greater flexibility in how the blockchain can be used.
The conservative stance
Resistance to these changes is being led by figures such as Luke Dashjr and BitcoinMechanic, who consider the expansion of the OP_RETURN limit a betrayal of Bitcoin’s fundamental principles. In their view, node operators should reject the storage of data unrelated to Bitcoin’s financial use case.
Conservatives argue that Bitcoin should not become a cloud storage service or a database for arbitrary data. The Bitcoin ledger, they maintain, should serve a narrow purpose: exclusively validating BTC movements for monetary use cases.
Version 30 release scheduled
The announcement of the October release date came via a post from Bitcoin Core developer Gloria Zhao, who confirmed the planned rollout for version 30.
While the default value will increase from 83 bytes to nearly 4MB, node operators will still be able to manually adjust the -datacarrier and -datacarriersize parameters. However, it’s widely acknowledged that most users stick with the default configuration.
Technical and philosophical implications
The controversy extends beyond purely technical matters, touching on fundamental questions about Bitcoin’s identity and future. Progressives see this evolution as necessary to keep Bitcoin competitive and versatile.
Conservatives, on the other hand, fear that allowing the storage of large amounts of arbitrary data could compromise network efficiency, increase node operation costs, and steer Bitcoin away from its original mission as a decentralized digital currency.
Community reactions
The debate has sparked tensions within the community. The technical editor of Bitcoin Magazine described conservatives as groups of people “clueless, and in some cases outright malicious and manipulative people on social media.”
On the other side, BitcoinMechanic called the progressives’ proposed changes completely “incoherent” with Bitcoin’s nature and objectives.
Jimmy Song also criticized the decision in a post on X, stating:
