On the main PHP.net site, they've posted the announcement of the release of the latest Release Candidate for the upcoming PHP 7.3.0 version: PHP 7.3.0.RC2.
The PHP team is glad to announce the next PHP 7.3.0 pre-release, PHP 7.3.0RC2. The rough outline of the PHP 7.3 release cycle is specified in the PHP Wiki.
[...] 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. Internal changes are listed in the UPGRADING.INTERNALS file. These files can also be found in the release archive.