On the main PHP.net site they've posted the announcement about the latest release in the PHP 7.1.x series: PHP 7.1.5. This is a bugfix release and problems were fixed in:

• core functionality
• date handling
• GD graphics functionality
• internationalization
• OpenSSL
• phar creation

You can download this latest release from either the main downloads page (source releases) or windows.php.net for the Windows binaries. If you're curious about the full set of changes, you can check out the full Changelog for this release.