Catenaa, Tuesday, January 06, 2026- Bitcoin Core, the reference software powering roughly 78% of Bitcoin full nodes, saw a notable rise in development activity in 2025, reversing a multi-year decline, according to Casa CSO Jameson Lopp.
Email traffic to the Bitcoin Development Mailing List, a forum for protocol proposals and debates, jumped 60% from 2024 levels.
The rebound follows a sharp decline in 2024, partly linked to the list’s migration from Linux Foundation servers to Google Groups.
The contributor base also grew. Lopp reported 135 individuals submitted code to the Bitcoin Core repository in 2025, up from about 112 the previous year.
Contributor numbers had peaked at 193 in 2018 and fell through most of the early 2020s. Code change volume, including lines added and deleted, totaled roughly 285,000, consistent with 2024 levels and the project’s historical pace.
The development uptick coincided with major technical milestones. Bitcoin Core completed its first public third-party security audit in November, led by cybersecurity firm Quarkslab and funded by nonprofit Brink, with no critical vulnerabilities detected.
Controversial mempool policy updates, including the removal of the 83-byte OP_RETURN limit in the v30 release, sparked intense discussion among developers.
Funding for Bitcoin Core continued from supporting organizations. VanEck maintained its pledge of 5% of spot Bitcoin ETF profits to nonprofit Brink, ensuring continued resources for development.
Analysts say the renewed developer engagement signals growing stability and ongoing innovation for Bitcoin’s protocol and ecosystem.
The trend marks a reversal of prior declines and suggests stronger long-term support for Bitcoin Core’s maintenance and advancement.
