How to Download WordPress Nightly Builds
WordPress development moves pretty fast. Often, changes in the software’s development cycle occur daily. While the developers are working on alpha and beta versions and release candidates, they commit the latest core changes to the repository and make those changes available to the public to download, install, and test on individual sites.
The changes are released in a full WordPress software package called a nightly build. This nightly build contains the latest core changes submitted to the project — changes that have not yet been released as full and final versions.
Using nightly builds isn’t a safe practice for a live site. I strongly recommend creating a test environment to test nightly builds. Many times, especially during alpha and beta phases, the core code breaks and causes problems with your existing installation. Use nightly builds in a test environment only, and leave your live site intact until the final release is available.
Hundreds of members of the WordPress community help in the development phases, even though they aren’t developers or programmers. They help by downloading the nightly builds, testing them in various server environments, and reporting to the WordPress development team by way of Trac tickets any bugs and problems they find in that version of the software.
You can download the latest nightly build from the WordPress repository.
Running the latest nightly build on your website is referred to as using bleeding-edge software because the software is an untested version, requiring you to take risks just to run it on your website.
WordPress Beta Tester, by Peter Westwood, is a super plugin that enables you to use the automatic upgrade tool in your WordPress Dashboard to download the latest nightly build.