Bitcoin Core v30 Upgrade Goes Ahead With Controversial OP_RETURN Data Limit Increase From 80 to 100,000 Bytes

Bitcoin Core developers announced the release of the highly controversial version 30.0 upgrade, which introduces a host of changes to node architecture, performance, and security. Most importantly, it raises the OP_RETURN data limit from 80 to 100,00 bytes, enabling larger non-financial data to be added to the blockchain.

However, this has split the Bitcoin community into two factions: the innovative advocates and Satoshi purists.

Core Devs Claim OP_RETURN Data Limit Expansion Supports More Sophisticated DApps on Bitcoin

The biggest upgrades brought forward in Bitcoin Core 30.0 are the release of optional encrypted connections between nodes for enhanced privacy and the increase of the OP_RETURN data limit within the software to 100,000 bytes. This enables significantly larger non-funancial data to be embedded in Bitcoin transactions.

The OP_RETURN expansion allows for more sophisticated decentralized applications and data-layer services to use Bitcoin’s settlement layer for timestamps, proofs, and state blogs. However, this has raised questions about the blockchain’s growth, higher storage requirements, and bandwidth needs for full nodes, and the potential legal risks for network operators who host arbitrary content.

The proposal was presented as a node software-level policy change rather than a consensus-layer protocol hard fork, which meant that miners and wallets were not required to accept larger OP_RETURN outputs unless they ran the updated Core v30 software. Therefore, the changes depend on adoption patterns among relays and archival operators.

Sunday’s release notes indicate that with the new major Core version now live, previous versions, such as v27.x and older, are at the end of their lives and will no longer receive updates.

Bitcoin Purists Argue Core v30 Deviates from Satoshi’s Vision

Bitcoin Core v30 update also includes bug fixes, performance enhancements, and changes to transaction fee rates; however, the move to increase the OP_RETURN limit has caused quite a divide within the Bitcoin community. The huge shift in data limits enables the deployment of more sophisticated and data-intensive decentralized applications (DApps) on the Bitcoin network, but this has angered purists who argue that the blockchain should only be used to conduct financial transactions.

Responses to the update have been mixed, with some developers and ecosystem leads welcoming the data flexibility. Ark Labs ecosystem lead Alex Bergeron wrote in an X post that the company plans to use the additional OP_RETURN space to make Bitcoin much more like Ethereum, “except better,” while Satoshi Labs co-founder Pavol Rusnak said that he opted for Bitcoin Core v30 because of it having a “great” development team, peer-reviewed code, and “sane” engineering decisions.

However, critics argue that Core v30 deviates heavily from Bitcoin’s fundamental principles of serving as a peer-to-peer electronic cash system, resulting in blockchain bloat, increased node operation costs, and legal issues. As a workaround, a significant number of nodes opposing the update have already been utilizing an alternative software known as “Bitcoin Knot”, which enables them to enforce the 80-byte size limit on transactions.

Pioneer cryptographer Nick Szabo recommended that operators run Knots as a “temporary measure” and rallied against upgrading to Core v30, warning about the legal risks if “illegal data” is hosted.

Luke Dashir, the founder of Knots, has been critical of the latest Bitcoin Core update, sharing concerns raised by node operators against hosting non-financial data. According to BitRef data, there are currently 5,114 nodes utilizing the Knots software, representing 21.48% of all nodes running the Bitcoin network.

Core vs Knots is the Second-Coming of 2017’s Block Size War

The ongoing debate has sparked memories of the block size wars of 2017, when operators debated over how to scale Bitcoin to handle increasing transaction volumes. The core issue at the time was whether to increase the 1 MB block size limit, originally set by Bitcoin’s inventor, Satoshi Nakamoto, to prevent spam attacks. But this became a bottleneck for the network as it gained popularity and expanded. 

The “Big Blockers” advocated for larger blocks to enable faster, cheaper transactions and promote mass adoption of Bitcoin as a global payment system. Meanwhile, the “Small Blockers” argued that maintaining a small block size is essential to preserve the blockchain’s decentralization, security, and ability for individual users to run full nodes.

The debate led to several proposed solutions, including the hard forking of the blockchain to create Bitcoin Cash (8 MB block limit) and Bitcoin Classic (2 MB limit), and the eventual implementation of Segregated Witness (SegWit) technology to increase capacity through a soft fork without changing the standard block size limit.

Bitcoin Core v30 is backward-compatible with earlier versions of the network, and all binaries are signed and available through bitcoincore.org and GitHub. Developers have already begun work on the next version, dubbed Bitcoin Core 31.0, which is expected to introduce peer-to-peer and UTXO management features in 2026.

At the time of writing, Bitcoin (BTC) is trading at $115,050 – up 2.97% in the last 24 hours.