Optech newsletter this morning covers the COLDCARD vulnerabilities, including urgent calls to action. As this is somewhat "breaking" news, if you have an important correction or clarification for this segment of the newsletter, please message me directly. As this is an evolving situation, and additional information is likely to emerge after this newsletter’s publication.

Brink is excited to announce that Martin Zumsande has (re)joined Brink to continue his work on Bitcoin Core including P2P networking, validation, testing, and review! Martin will focus on researching address relay propagation, improving block download reliability, closing a privacy leak in wallet transaction rebroadcast, and expanding validation fuzz testing, in addition to continued code review. https://brink.dev/blog/2026/07/22/martin-zumsande/