If you’re new to Bitcoin or the only sats you hold are in an ETF or a centralized exchange, you’d be forgiven for not knowing about Core vs Knots and the entire OP_RETURN saga. But if you’ve weathered a few cycles, HODLed like a champ, and are still scratching your head, it’s time you opened your eyes: the 2025 ‘spam wars’ bear all the hallmarks of the block size wars almost a decade before it, and it’s getting ugly fast.
Like the block size wars, the spam wars involve a fundamental ideological clash over the core principles of Bitcoin, particularly scaling versus decentralization, and whether to prioritize network capacity and ease of use over a simpler, permissionless protocol.
Supporters of Bitcoin Core, the long-standing reference implementation, and Bitcoin Knots, an increasingly popular alternative maintained by developer and CTO at Ocean Mining, Luke Dashjr, are at loggerheads, and the gloves are coming off.
Core vs Knots, what’s happening?
At the center of the controversy is Bitcoin Core’s planned removal of the 80-byte limit on OP_RETURN data in its upcoming v30 release, scheduled for October 2025.
This technical change, intended to boost flexibility and unlock new use cases for embedding data on Bitcoin’s blockchain, is fiercely opposed by Knots backers, who argue it transforms the main network into a dumping ground for non-financial transactions and spam.
Core developers, like Peter Todd and Jameson Lopp, claim the change supports broader innovation, like digital art and document verification. They support everyone’s right to use the Bitcoin blockchain as they feel and not have governance or morals thrust upon them. Lopp posted:
“I truly detest politics. Thus I have little patience for those who try to impose traditional governance models onto Bitcoin. If you don’t like anarchy, you’re free to leave.”
Knots supporters like Samson Mow and Luke Dashjr warn that the upgrade risks bloating the blockchain, undermining Bitcoin’s neutrality, and weakening its monetary purpose. Dashjr warned:
“What do you think will happen now that Core is opening the floodgates to spam, and essentially endorsing it? (No matter what they say, that’s how spammers will take it.) Any chance we have of making Bitcoin a success will go out the window – unless the community takes a clear stand and rejects the change.”
Network philosophy and neutrality
The Core vs Knots dispute highlights deeper ideological rifts about Bitcoin’s function. Should Bitcoin remain a strictly monetary settlement layer, or can it evolve to serve more experimental on-chain data needs, so long as fees are paid?
Core’s apparent policy shift is seen by some as relinquishing its gatekeeping role, allowing any use case if the user pays. Knots supporters, however, emphasize control with features like anti-spam protection and argue that the removal of data caps could centralize power and threaten scalability.
Miners and relay service operators play a pivotal role, determining which transaction types end up in blocks and how the network responds to diverging software preferences. Node operators, too, have increasingly migrated to Knots: its share of the network doubled over six weeks in May-June 2025, and has now reached ~17% of all Bitcoin nodes, a sign of growing protest and possible fragmentation ahead of Core’s v30 launch.
Where is it heading?
While there is no hard fork yet, mounting tensions and the possibility of blocks or transactions being rejected by different software clients evoke memories of the 2017 SegWit split.
The Core vs Knots scenario also raises another fundamental issue surrounding the true decentralization of the Bitcoin network: how many of Bitcoin’s supporters run their own node? Dashjr posted:
“Bitcoin’s greatest threat to survival is that far too few people are using a full node. For Bitcoin to work, at least 85% of economic activity needs to do so.”
With technical, political, and philosophical stakes at play, October’s Core v30 release may define the next era of Bitcoin development and decentralized consensus, determining whether diversity in software serves Bitcoin’s resilience or sparks an outright chain split.