PHP 7.2 has been released, bringing some great new features and security enhancements to the language such as object type hints, saner count() behavior, and much more. Here's a brief guide on how to install PHP 7.2 on several different operating systems.
Using brew on MacOS it's very easy to upgrade from PHP 7.1 to PHP 7.2. Just run these:
brew update brew upgrade brew unlink php71 brew install php72
Please be aware that, at the moment of writing, there isn't a stable xdebug version that works for PHP 7.2. Keep an eye on the xdebug homepage to know when a stable version drops.