If you’re just starting with Bitcoin or your only satoshis are in an ETF or on a centralized exchange, you might not be familiar with the Core vs. Knots debate and the OP_RETURN issue. But if you’ve seen a few market cycles, held your ground, and still find yourself confused, it’s time to pay attention: the 2025 ‘spam wars’ echo the block size wars from nearly a decade ago, and the situation is escalating quickly.
Similar to the block size conflict, the spam wars are rooted in a fundamental ideological disagreement regarding Bitcoin’s core principles, particularly the balance between scaling and decentralization, and whether to prioritize capacity and user-friendliness over a simpler, permissionless framework.
Supporters of Bitcoin Core, the long-established reference implementation, and Bitcoin Knots, a rising alternative developed by Luke Dashjr, CTO of Ocean Mining, are in a heated disagreement, with tensions rising.
Core vs. Knots, what’s unfolding?
The crux of the issue lies in Bitcoin Core’s upcoming decision to eliminate the 80-byte limit on OP_RETURN data in its version 30 release, slated for October 2025.
This technical modification, aimed at enhancing flexibility and opening new possibilities for data embedding on Bitcoin’s blockchain, faces strong opposition from Knots supporters, who argue it would turn the main network into a repository for non-financial transactions and spam.
Core developers, including Peter Todd and Jameson Lopp, argue that this change will foster broader innovation, such as in digital art and document verification, asserting that users should have the freedom to use the Bitcoin blockchain as they see fit without governance or moral constraints. Lopp stated:
“I genuinely loathe politics. Therefore, I have little tolerance for those attempting to impose conventional governance structures on Bitcoin. If anarchy doesn’t suit you, feel free to leave.”
On the other hand, Knots proponents like Samson Mow and Luke Dashjr caution that the upgrade risks bloating the blockchain, undermining Bitcoin’s neutrality and jeopardizing its monetary function. Dashjr alerted:
“What will occur now that Core is effectively inviting spam? (Regardless of their claims, that’s how spammers will perceive it.) Any hope for Bitcoin’s success could vanish—unless the community firmly stands against this change.”
Network philosophy and neutrality
The Core vs. Knots debate reveals deeper ideological divides about Bitcoin’s role. Should Bitcoin strictly serve as a monetary settlement layer, or can it also cater to more experimental on-chain data requirements as long as fees are covered?
Core’s apparent policy shift is viewed by some as giving up its oversight authority, permitting any use case as long as users pay. Knots advocates, however, stress the need for control through anti-spam features, arguing that lifting data limits could centralize authority and compromise scalability.
Miners and relay service operators have a critical influence, deciding which transaction types are included in blocks and how the network reacts to different software preferences. Notably, node operators have increasingly shifted towards Knots: its share of the network doubled during May and June 2025, reaching ~17% of all Bitcoin nodes, indicating rising dissent and potential fragmentation ahead of Core’s v30 rollout.
Where is this headed?
Although a hard fork has not yet occurred, rising tensions and the prospect of blocks or transactions being rejected by differing software clients bring to mind the 2017 SegWit split.
The Core vs. Knots situation also surfaces essential questions about the genuine decentralization of the Bitcoin network: how many of Bitcoin’s advocates operate their own nodes? Dashjr asserted:
“Bitcoin’s most significant threat to its survival is that too few individuals are utilizing a full node. For Bitcoin to function, at least 85% of economic activity needs to do so.”
With various technical, political, and philosophical issues at stake, the upcoming Core v30 release in October may define a new chapter in Bitcoin’s development and decentralized consensus, influencing whether software diversity enhances Bitcoin’s resilience or leads to an outright chain split.
