Devtools 1.10.0 is now available on CRAN. Devtools makes package building so easy that a package can become your default way to organise code, data, documentation, and tests. You can learn more about creating your own package in R packages. Install devtools with:

install.packages("devtools")

This version is mostly a collection of bug fixes and minor improvements. For example:

• Devtools employs a new strategy for detecting RTools on windows: we now only check for Rtools if you need to load_all() or build() a package with compiled code. This should make life easier for most windows users.
• Package installation receieved a lot of tweaks from the community. Devtools now makes use of the Additional_repositories field, which is useful if you’re using drat for non-CRAN packages. install_github() is now lazy and won’t reinstall if the currently installed version is the same as the one on github. Local installs now add git and github metadata, if available.
• use_news_md() adds a (very) basic NEWS.md template. CRAN now accepts NEWS.md files so release() warns if you’ve previously added it to .Rbuilignore.
• use_mit_license() writes the necessary infrastructure to declare that your package is MIT licensed (in a CRAN-compliant way).
• check(cran = TRUE) automatically adds --run-donttest as this is a de facto CRAN standard.

To see the full list of changes, please read the release notes.