The industry is divided over the release of Bitcoin Core v30.0, with repeated opposition to OP_RETURN extension.

A new controversy has emerged within the Bitcoin Core community. Regarding the officially released Bitcoin Core v30.0, which involves an extension of the OP_RETURN data limit (from 83 bytes to 100KB), intense debates are ongoing between developers and node operators.

What is causing the controversy

Critics led by the Bitcoin Knots community, headed by Luke Dashjr, are strongly opposed to the 100-fold increase in data capacity. Their main argument is clear: if large amounts of data can be stored in OP_RETURN, there is a risk that node operators could unknowingly host illegal content or harmful information. They are concerned that this could ultimately lead to legal liabilities.

On the other hand, the Bitcoin Core development team argues, “This is merely an adjustment to mempool policies and does not affect Bitcoin’s consensus rules.” Essentially, the positions remain deadlocked.

During the development phase in September, there was a plan to completely eliminate the option for users to adjust data limits, which sparked further backlash. However, just before the release in October, maintainer Ava Chow reversed this stance. The reintroduction of configurable settings temporarily eased tensions.

Is a hard fork possible?

Leaked internal messages have led to speculation that Dashjr was considering a network split. It was reported that he might have been preparing a fork under the pretext of protecting nodes from illegal data dissemination.

However, Dashjr denied this, calling it “fake news” and explicitly stating, “There are no plans for a hard fork.” Nonetheless, his opposition remains firm, and he has countered by claiming, “Supporters of Core 30.0 are the ones proposing a fork.”

What is included in v30.0

There are also significant technical improvements. First, the fee structure has been optimized. Transaction relay fees between nodes have been lowered to 0.1 sat/vB, and the minimum accepted fee for miners has been reduced to 0.001 sat/vB.

Regarding OP_RETURN, support for multiple outputs has been added, allowing for more flexible data inclusion such as hashes, certificates, and art metadata.

Wallet functions have also been greatly revamped. The old BDB wallet has been deprecated, and migration to a more secure and easily recoverable descriptor wallet is now mandatory. Traditional commands like importwallet and dumpwallet have been removed.

A new TRUC feature has been introduced to prevent conflicts with transactions waiting for confirmation, and an experimental PC mining interface will be available for miners. This allows direct connection to Bitcoin Core via local sockets and improves the speed of block template requests.

UI/UX evolution

The GUI toolkit has been upgraded from Qt5 to Qt6. On Windows, dark mode support has been added, and on macOS, Metal graphics are now used, providing a more refined visual experience.

A new command-line tool called “bitcoin” has been introduced, simplifying operations for node operators and miners. The previous multiple command systems have been unified into three categories: bitcoin node, bitcoin gui, and bitcoin rpc.

Future roadmap

Bitcoin Core v27.x has already been marked as “End of Life,” and will no longer receive security updates. Details of five low-priority bug fixes are scheduled to be announced within two weeks.

The behavior of the -datacarriersize parameter has also been changed. Previously, a value of “83” indicated an 83-byte limit, but in v30, the same value now allows over nine times more data. Critics have pointed out that this quiet change could lead to user misunderstandings.

Currently, users can manually lower the new default setting of 100KB if they choose.