Bitcoin Core developers are preparing to roll out the highly anticipated — and controversial — Bitcoin Core v30 update, with a second release candidate (v30.0rc2) now available for testing. The final release is expected as early as late October, pending further evaluation.

The upgrade introduces a new wallet format and phases out legacy infrastructure, streamlining Bitcoin’s command system. But the most divisive feature is the expansion of OP_RETURN, the opcode that allows embedding arbitrary data into transactions. The current 80-byte default cap could be effectively lifted to nearly 4 MB per transaction output, opening the door to greater non-financial data storage on-chain.

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Purists vs. Maximalists

The change has reignited an old fault line within the Bitcoin community. Purists argue that Bitcoin should remain strictly a monetary network, warning that excessive OP_RETURN usage could bloat the blockchain, increase storage costs for node operators, and create vectors for spam or even malware.

Maximalists counter that block space should remain open to all valid uses so long as fees are paid, with market dynamics naturally regulating demand and discouraging abuse.

Bitcoin Core developers have signaled support for the upgrade, though the timeline remains fluid amid ongoing technical scrutiny and philosophical clashes over Bitcoin’s role.

Nick Szabo Raises Legal Concerns

Adding fuel to the debate, cypherpunk pioneer Nick Szabo — often speculated to be Bitcoin’s elusive creator, Satoshi Nakamoto, though he has denied the claim — resurfaced on X after nearly five years of silence to voice concerns.

Szabo acknowledged that fees function as a “spam filter” protecting miners, but argued they do not adequately shield full nodes from the burdens of permanently storing arbitrary data. Expanding OP_RETURN, he warned, could heighten legal risks.

“It’s an open legal issue almost everywhere,” Szabo wrote, suggesting that node operators could face potential liability for harmful or illegal data embedded in the blockchain. While some argue OP_RETURN’s prunable nature may reduce risks compared to hidden data, Szabo countered that standardized formats could actually make illicit content more visible and therefore more legally problematic.

His intervention carries weight given his long-standing influence in cypherpunk circles. Earlier this year, Szabo joined Samson Mow’s Bitcoin infrastructure firm Jan3 as chief scientist, reinforcing his ongoing role in shaping Bitcoin’s future.

A Pivotal Moment for Bitcoin

As testing progresses, the debate over Bitcoin Core v30 highlights the network’s enduring tension between innovation and preservation. Whether OP_RETURN expansion represents progress or peril will ultimately depend on how the community, miners, and regulators respond once the update goes live.

Bitcoin pioneer Szabo returns to X to join the debate. Source: Nick Szabo