Bitcoin code controversy ignites developer split! Core v30 is criticized as "malware"

Bitcoin Core v30.0 update raised the OP_RETURN data limit from 80 bytes to 100,000 bytes, triggering an unprecedented split crisis in the Bitcoin developer community. Notable developer Luke Dashjr criticized this as “malware” and called for a mass migration, but Blockstream CEO Adam Back countered that critics are “attacking Bitcoin.”

Bitcoin Core v30 Core Controversy: OP_RETURN Expansion Ignites Warfare

The mainstream software Bitcoin Core, which supports about 80% of BTC nodes, officially released the v30.0 update on October 11. This update brings improvements in encrypted node connections, performance optimization, cost improvements, and several bug fixes, but the real trigger for the community split is the significant changes to the built-in “data graffiti wall” OP_RETURN.

· What is OP_RETURN? Why has it become the core of the conflict?

OP_RETURN allows users to attach metadata such as text, images, or digital signatures to Bitcoin transactions without affecting their monetary function. Previously, each OP_RETURN output could carry a maximum of 80 bytes of data, a limitation that strictly controlled the scope of non-financial use cases.

Key changes in v30.0:

Data limit expansion: from 80 bytes to 100,000 bytes (1,250 times expansion)

Multi-output support: Allows each transaction to default to multiple OP_RETURN outputs for relaying and mining.

No manual configuration required: Node operators running v30 can automatically handle transactions that embed larger or more complex data structures.

In practical application terms, this means that the Bitcoin blockchain can now support a variety of complex data structures ranging from NFT-style inscriptions to application metadata, without the need for additional configuration by node operators.

Bitcoin developers split into two factions: Innovation vs. Expansion Debate

The change in this Bitcoin code has sparked intense debates within the developer community, with clear divisions between the two camps.

· Support Party: The Value of Uncensorable Historical Records

Supporters believe this is a necessary path for the natural evolution of Bitcoin, allowing it to be compared with smart contract blockchains like Ethereum. A market analyst emphasized: “The original intention of OP_RETURN was designed for usage. Imagine how powerful a non-censorable, unalterable registry would be. Winners cannot rewrite history. Humanity can record history from its own perspective at that specific moment. This is a goldmine for future historians and an incredible leap for humanity.”

· Opposition: Luke Dashjr criticizes “malware”

Prominent developer Luke Dashjr strongly criticized this change, calling Core v30 a “destruction” of the data carrier size control and completely abandoning it, allowing more “spam output” for each transaction.

His core arguments include:

Deviation from original design: Bitcoin does not support data storage exceeding 80 bytes (OP_RETURN) or block 95 bytes, which should be related to financial transactions.

Abuse of script opcodes: Use cases such as inscriptions exploit vulnerabilities and are not supported actions; they merely damage Bitcoin with forged junk scripts.

Security risk upgrade: Expanding OP_RETURN may provide sufficient storage space for illegal content (such as CSAM)

For these reasons, Luke Dashjr characterized v30 directly as “malware” and urged the community to “migrate en masse to Knots”—an alternative client implementing stricter policies.

Blockstream CEO strikes back: Criticism equals attacking Bitcoin

Blockstream CEO Adam Back strongly rebutted, stating that disparaging changes to OP_RETURN is equivalent to “attacking Bitcoin.” He emphasized that this update includes legitimate security and robustness fixes from “some of the most skilled developers on the planet” and should not be stigmatized.

· Blockchain Inflation Crisis: How the Data Flood Will Change Bitcoin

(Source: Mempool Research)

According to Mempool Research data, inscriptions and OP_RETURN transactions currently account for Bitcoin's:

40% of all transactions (based on the number of transactions)

10% transaction fee

28% block weight

If these data-intensive transactions are more widely adopted, the average block size of Bitcoin may increase from the current 1.5 MB to 4 MB per block—this will fundamentally reshape the economic structure of the network.

Potential Impacts in Three Major Areas

1. Cost Pressure Upgrade

Injecting large data files into the memory pool may accelerate cost competition, and small transaction users will face higher costs.

2. Node operation threshold raised

The expansion of blockchain will increase storage and bandwidth demands, potentially reducing the level of decentralization.

3. Diversification of Use Cases

Supporting more complex data structures may attract new application scenarios, but it may also dilute Bitcoin's core positioning as a peer-to-peer financial network.

Compromise Solution Emerges: OP_Return2 and Trimming Mechanism

Faced with the deadlock of Bitcoin developers' split, the community has proposed several compromise solutions at the policy level.

Nick Szabo's Incremental Approach:

From now on, the OP_RETURN feature will no longer be used for financial transactions.

Add the ability to trim newer OP_RETURN while retaining the older OP_RETURN.

CEX Exchange Research Proposes the Concept of OP_Return2:

The soft fork mechanism allows the submission of hash values of up to 8 MB of external data for transactions.

No need for mandatory full node verification or storage

Reduce on-chain bloat while maintaining data integrity.

However, researchers warn that if the costs cannot offset the additional complexity, miners may lack the incentive to add such transactions. Moreover, similar timestamp features already exist at a lower cost.