PHP 7.2 was released last week. Here's a nice post highlighting the most important changes. If you want to know how to install PHP 7.2 on your system, Colin O' Dell has got you covered.

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.

https://www.colinodell.com/blog/201711/installing-php-72

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.