In December 2015, PHP 7.0 was released, marking a new milestone for PHP and web application developers. Looking at the changelog and removed functions, we thought all was going to be easy to migrate to PHP 7.0. Unfortunately, many of the extensions and tools we use weren't ready yet. In December 2016, PHP 7.1 was released and the urgency to update became real as PHP 5.6 was nearing end-of-life. In this talk, I describe the analysis and the challenges we faced migrating towards PHP 7.1 so you can learn how to defeat those challenges if you plan to migrate too.