BIP-110 update: v0.4.1 release and implementation submitted to Bitcoin Core

The recent update on BIP-110 includes the release of version 0.4.1, which was first proposed in October 2025 and is a significant development aimed at enhancing Bitcoin's functionality by limiting data field sizes within transactions. This proposal specifically restricts all officially supported methods of data storage to 256 bytes or less, thus preserving Bitcoin's monetary use without supporting data storage as a primary function. The benefits of such a limitation include reducing the demand for arbitrary data storage, aligning consensus and policy more closely, ensuring the decentralization of node networks by avoiding unnecessary burdens, and maintaining Bitcoin’s utility as a currency.

The v0.4.1 activation client, a fork from Bitcoin Knots labeled bitcoin-29.3.knots20260210+bip110-v0.4.1, has been stable for weeks despite initial bugs. The updated consensus rules specify constraints on scriptPubKeys, OP_RETURN, and other elements while providing exemptions for UTXOs created before the activation height. These rules are set to expire after approximately one year, aiming for potential activation around December 2025 if 55% of hashpower signals support by then.

For deployment, BIP-110 is compatible with various platforms including Umbrel, MyNode, Start9, and Parmanode, among others. It is available through Guix reproducible builds with binaries accessible for multiple OS via the GitHub Release page. The proposal's implementation has gained traction, accounting for over 8% of listening nodes within two months of its release.

Further technical steps include the submission of BIP-110’s implementation to Bitcoin Core, with PRs split across enhancements and rule implementations. Although initially closed by an automated process, discussions and reviews continue on mirror PRs. This integration into Bitcoin Core is crucial for ensuring that nodes adhere to validated chains once BIP-110 is activated. Moreover, the community engagement and technical feedback are encouraged to refine and optimize the implementation, reflecting a collective effort to evolve Bitcoin's infrastructure responsibly.