The main PHP.net site has announced the release of the latest Release Candidate for the upcoming PHP 7.1.0 version - PHP 7.1.0 RC2.
The PHP development team announces the immediate availability of PHP 7.1.0 Release Candidate 2. This release is the second release candidate for 7.1.0. All users of PHP are encouraged to test this version carefully, and report any bugs and incompatibilities in the bug tracking system.
For more information on the new features and other changes, you can read the NEWS file, or the UPGRADING file for a complete list of upgrading notes. These files can also be found in the release archive. [...] The third release candidate will be released on the 29th of September. You can also read the full list of planned releases on our wiki.
They include the usual reminder that this is a preview release and is not intended fro production use. If you'd like to test it out with your application, you can download the source release here or go to the windows.php.net QA site to get the Windows binaries.