Performing the migration

Performing the actual migration from your current version to PHP version 8 is much like the process of deploying a new set of features to an existing application. If possible, you might consider running two websites in parallel until such time as you are confident the new version works as expected. Many organizations run the staging environment in parallel with the production environment for this purpose.

In this section, we present a twelve-step guide to perform a successful migration. Although we are focused on migrating to PHP 8, these twelve steps can apply to any PHP update you may wish to perform. Understanding and following these steps carefully is critical to the success of your production website. Included in the twelve steps are plenty of places where you can revert to an earlier version if you encounter problems.

Before we get into details, here is a general overview of a twelve-step migration process going from an older version of PHP to PHP...