Bitcoin Core, Satoshi Nakamoto's full-node implementation of the Bitcoin Protocol, has increased the much debated OP_RETURN Limit.
OP_RETURN Limit:- In a move that has settled the dust on the long-standing debate, the Bitcoin Core development team has confirmed plans to release version 30 of its reference implementation this October.
The upgrade will be featuring a landmark change to the OP_RETURN data limit. Under the new rules, users will be able to embed up to 4 MB of arbitrary data in a single OP_RETURN output – up from the longstanding 80-byte ceiling imposed in 2014.
The update represents one of the most significant technical shifts in Bitcoin’s two-year-old block size regime. It has also reignited debates around blockchain utility and efficiency.
What’s the update Bitcoin Core is Bringing
OP_RETURN outputs allow users to include metadata such as messages, timestamps, or small files directly in the blockchain without creating spendable UTXO entries.
Prior to Core 30, these outputs were capped at 80 bytes, limiting on-chain inscriptions to ultra-small payloads. In practice, the limit has driven many projects to hack around the constraint or resort to off-chain storage solutions.
However, with the proposed merger, the Version 30 will effectively remove the strict 80-byte barrier. It will instead be permitting OP_RETURN fields to grow up to the maximum block size (nearly 4 MB), provided operators run default settings.
Rationale Behind the Expansion by Bitcoin Core
Proponents argue that enlarging OP_RETURN capacity will streamline certain data-anchoring use cases. Developers can embed entire documents, digital certificates, or decentralized identifiers directly on-chain without off-chain workarounds.
Projects can store larger media assets (e.g., images, small audio clips) in OP_RETURN outputs, broadening Bitcoin’s role beyond pure value transfer.
Gloria Zhao, a core contributor to Bitcoin Core, explained in a X post on June 9, “This update modernizes Bitcoin’s data carrier functionality and better aligns on-chain capabilities with evolving developer needs, all while preserving decentralization. Operators displeased with the change can still configure custom limits, though these options may be phased out in later releases”.
Why Critics are Calling the Update as “Spam”
The proposal has reignited a longstanding ideological split between “progressive” and “conservative” factions within Bitcoin’s developer and node-operator communities.
Critics caution that lifting the OP_RETURN limit could pave the way for blockchain “spam” as more data can be infiltrated on the blockchain. This can undermine network performance and contravene the protocol’s original peer-to-peer monetary vision. A vocal opponent on social media warned, “If you still run Core, I very strongly urge you to switch to Bitcoin Knots or not update Core—Bitcoin Core is now fully malicious”.
I fear we’re paving the way for blockchain spam—why allow megabyte-scale data pushing through every node?” posted long-time node-operator LukeDash on Twitter.
However, supporters counter that expanded data capacity remains voluntary and that the majority of node operators prioritize utility and innovation.
Satoshi Action Fund Stops Funding Bitcoin Core
Amid the ongoing controversy surrounding the Bitcoin Core upgrade, Satoshi Action Fund (SAF) has stopped its funding to the Bitcoin Core.
Dennis Porter, co-founder of the fund said, “My faith in their work is now broken.”.
He publicly stated that he personally helped raise over $200,000 for Bitcoin Core developers through the Fund.
SAF’s departure represents a $200 000 funding hole for Core which is about 18 % of what MIT committed back in 2019. Though it is a fraction of total ecosystem grants but still a meaningful loss of discretionary developer funding.
Implications for Bitcoin’s Evolution
With Bitcoin Core powering over 90 percent of full nodes on the network, any protocol-level change carries substantial weight.
The OP_RETURN expansion could enable new classes of on-chain applications. These can range from decentralized content anchoring to complex multi-party contracts—without necessitating secondary layers.
Yet the debate highlights broader tensions: how to balance Bitcoin’s foundational focus on monetary security with burgeoning demands for programmable blockchain features.
As Core 30’s release date approaches, all eyes will be on node-operator adoption rates. It also remains to be seen whether this update settles or further inflames the discourse on Bitcoin’s purpose and trajectory.
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