Bitcoin Core 30.0 Introduces Major Upgrades — OP_RETURN Limit, Security, and Usability in Focus

Market Context

As Bitcoin matures, its protocol development must balance decentralization, usability, and scalability. Core updates often face scrutiny from node operators, developers, and the broader community. In an environment where stakeholders are pushing for greater programmability and integrations (e.g. Runes, ordinals), Bitcoin Core 30.0 arrives at a critical juncture for how “store of value” and “data layer” interpretations coexist.

Technical Details & Attribution

Bitcoin Core 30.0 introduces a series of notable changes: 

• Signature Operations Cap: Standard transactions are now limited to 2,500 signature operations, reducing complexity in overly “heavy” transactions. 
• Datacarrier Size Default: The -datacarriersize parameter’s default is now 100,000 bytes, enabling much larger data attachments.
• Multiple OP_RETURN Outputs: Transactions may include more than one OP_RETURN output, facilitating more complex non-financial data embedding. 
• Orphan Transaction Buffer Redesign: The orphan buffer was overhauled to improve Denial-of-Service (DoS) resistance. 
• External Signature Support (Windows): Reintroduced to improve compatibility for signers on Windows platforms.
• Mining IPC / Stratum v2 Support: Adds support in the mining interprocess communication (IPC) layer, including alignment with Stratum v2 protocols. 
• Coinstatsindex Update: Changes to the coinstatsindex component to refine blockchain statistics capabilities.
• RPC Changes & Usability Features: Enhanced command-line tools (e.g. ability to launch external executables), migration tools for legacy wallets, UI updates (Qt5 to Qt6, dark mode, macOS support). 
• EOL for Older Versions: Branches 27.x and earlier are now officially End of Life (EOL). 

Controversial Highlight — OP_RETURN Expansion
Perhaps the most discussed change is the OP_RETURN limit expansion—from the prior 80 bytes to 100,000 bytes. This allows for significantly more non-financial data to be embedded in transactions. Supporters argue it simplifies and expands functionality (e.g. for the Runes standard), while critics warn of potential blockchain bloat, node burden, or misuse. 

Nick Szabo cautioned that embedding large arbitrary data could expose nodes to risks (e.g. illegal content), and suggested alternatives like selective removal.  Peter Todd countered, saying Bitcoin already supports these patterns and this change streamlines them. 

Analyst Perspectives 

Many technologists view Core 30.0 as a necessary modernizing step—one that balances innovation with protocol conservatism. The additional data capacity for OP_RETURN is seen by some as enabling growth in novel use cases (like inscriptions, better metadata standards) without forking. But others caution that network strain, storage costs, and node operator burden may grow if collective discipline is not maintained.

The success of this upgrade will depend on adoption rates among node operators, wallet compatibility, and how the market and developer community respond to new capabilities.

Global Impact Note

If the changes prove stable and beneficial, Bitcoin’s ability to carry richer data (not just value transfers) could strengthen its role in broader ecosystems—e.g. as a timestamping layer, metadata anchor, or immutable registry backbone. Across jurisdictions, standards adopting Bitcoin for nonfinancial data anchoring may emerge. That said, the community must remain vigilant against network centralization pressures from data burden or hardware requirements.