Dear Boost Community: The Boost Formal Review of the *Corosio* and *Capy* libraries will begin on *June 23, 2026* and will conclude on *July 7, 2026*. I'm Jeff Garland and I'll be the review manager. I'd like to thank Vinnie for inviting me to maintain the continuity from Boost.Asio and I'll apologize now for the late notice. Since this is a two library review the period is somewhat extended from normal. In fact my personal pre-review indicates we will likely need an extension due to the size of the libraries -- I'll work with the review wizards on that. Capy Capy is a coroutine foundation library providing task types, execution contexts, executors, asynchronous synchronization primitives, buffer abstractions, and coroutine composition facilities. It serves as the execution and asynchronous programming substrate upon which Corosio is built. Repository: - Capy GitHub Repository <https://github.com/cppalliance/capy?utm_source=chatgpt.com> - docs <https://develop.capy.cpp.al/capy/index.html> Corosio Corosio is a coroutine-native asynchronous I/O library for C++20. It provides networking and I/O facilities designed specifically for coroutines, with awaitable operations, executor affinity, cancellation support, and cross-platform implementations based on IOCP, epoll, and kqueue. Repository: - Corosio GitHub Repository <https://github.com/cppalliance/corosio?utm_source=chatgpt.com> - docs <https://develop.corosio.cpp.al/corosio/index.html> Review Questions Potential reviewers are encouraged to consider the following questions: 1. What is your evaluation of the usefulness of the libraries? 2. What is your evaluation of the design? 3. What is your evaluation of the implementation? 4. What is your evaluation of the documentation? 5. Have you used either or both libraries? What was your experience? 6. Are the libraries ready for inclusion in Boost? 7. If not, what changes would you recommend before acceptance? 8. Do the libraries fit well within the existing Boost ecosystem? 9. Are there API, naming, usability, extensibility, or implementation concerns that should be addressed? How to Participate Please post your review to the Boost Developers mailing list. Reviews from both experienced Boost contributors and first-time reviewers are encouraged. Reports based on real-world usage, experimentation, code inspection, and documentation review are all valuable contributions. At the conclusion of the review period, the review manager will consider all feedback and determine whether the libraries should be accepted into Boost. We look forward to your participation in this review.