Somewhere in the frontmatter, possibly just before the introduction? we'd like the following note about the version and edition of Rust used for this printing of the book. We're open to other locations if you think somewhere else would be best.

## Note on Rust Version and Edition

This version of the text assumes you are using Rust 1.31.0 or later, with
`edition="2018"` in *Cargo.toml* of all projects to use Rust 2018 Edition
idioms. See the "Installation" section of Chapter 1 on page XX to install or
update Rust, and see Appendix E on page XX for information on what editions of
Rust are.
