On the PHP.net site they've posted the announcement about the release of the latest alpha in the PHP 7.2.0 series: PHP 7.2.0 Alpha 3

The PHP development team announces the immediate availability of PHP 7.2.0 Alpha 3. This release contains fixes and improvements relative to Alpha 2. All users of PHP are encouraged to test this version carefully, and report any bugs and incompatibilities in the bug tracking system.

This release is intended for development only and is not to be used in production. The NEWS section for this release contains updates that are new to this alpha, mostly around bugfixes (but some new features are slowly working in for the final 7.2.0 release). As always you can download the source packages from the QA downloads page or grab the Windows packages for this alpha from the Windows QA site.