We currently use PHP 7.0 as stable version when publishing our PHP solutions. We have other apps that require PHP 7.1 or 7.2 to work and we published them with that version. I'll share your information with the Engineering team so they will evaluate it and work on publishing a new solution of Magento.
Meanwhile, you can install the Bitnami LAMP 7.1 stack in your current server and then install the Magento module on top of it
Let us know if you have any questions about this process