BTC Core 30 Schedules Removal of OP_RETURN Byte Limit
In brief
- Effective Date: Bitcoin Core 30 update scheduled for October 30 will remove the 80-byte OP_RETURN data limit.
- Key Change: Allows transactions up to 4MB of arbitrary data per output.
- Debate Point: Critics argue the move shifts Bitcoin’s focus from peer-to-peer payments to data storage.
Bitcoin’s core developers have confirmed plans to eliminate long-standing data storage restrictions in the upcoming Core 30 release, set for release on October 30.
The policy shift essentially removes Bitcoin’s 80-byte cap on OP_RETURN outputs, special transaction fields enabling the embedding of arbitrary data on the blockchain. The update permits multiple OP_RETURN outputs per transaction, each limited to four megabytes of data.
Awareness
“Bitcoin Core is just one protocol implementation that can be copied and modified by anybody; the only thing that makes it special is the way its contributors make decisions.”
@glozow
Implementation Details
Changes go into effect with Core v30. The pull request modifies the default value for the -datacarriersize parameter. Users will retain the ability to use -datacarrier and -datacarriersize options in v30; manual configuration to restore the 80-byte limit remains possible during this version. Eventually, however, these options will be entirely removed.
The update aligns Bitcoin Core’s block data handling rules more closely with miner acceptance. Core developers aim to reduce the need for block size consuming transactions to be relisted via centralized channels outside the public mempool.
The OP_RETURN Divide
The policy change follows months of heated debate among the Bitcoin community. Proponents see it as a fundamental step towards a programmable Bitcoin supporting broader use cases. Critics, notably long-time contributor Jason Hughes, believe the change fundamentally alters “the nature of what the Bitcoin network itself is in its entirety.”
Gloria Zhao, a core contributor, stated the “primary motivation” was addressing perceived harmful methods for storing bloating data on the network. Core rules stricter than miner enforcement created pressure towards centralization, she explained, undermining censorship resistance. Removing OP_RETURN limits would align policy with “mining realities.”
The announcement drew sharp criticism from the community. Engineer Juan David Diaz commented, “There was no clear consensus on this, and therefore should have been never merged!” while another pseudonymous contributor argued, “There is no consensus for this change.”
