Upgrading a website script version is one of the highest risk procedure a webmaster has to deal with when managing a website. Migrating from Drupal 7 to Drupal 8? Here is a small guide with various details. Let’s start with basic info : Note that you don’t need to know anything about PHP to build a site in Drupal. When you search (preferably on Google) for a solution to your latest Drupal problem, a lot of the pages that come up will be providing snippets of PHP code. This is not the correct help information for you, the Drupal newbie. This is for technically competent people who are able to build their own modules and stuff like that. If you look at the other pages thrown up by your search, you will probably find an answer to your problem which involves working within the existing Drupal core and modules. That means, a solution you can implement using menus and tickboxes and whatnot, without needing to mess around with code.
The very first thing you should do is to make a local version of the website. This is an essential step because making changes to a live website is very risky and is never a recommended practice. This way, if anything does go awry, your actual website will remain safe and functional. After clicking Continue, you will be brought to the screen in the following screenshot. Enter all the required details such as your existing website’s credentials, the database location and the location of your website files.
Upgrading is the process of moving your site from a previous major version of Drupal to a newer version, for example from Drupal 7 to Drupal 8. This consists of upgrading the codebase to the appropriate version and then migrating the data from your old site into the new one. Drupal 8 core contains two modules to help facilitate this process: Migrate Drupal and Migrate Drupal UI.
The steps above outline how to get a distribution minimally installed on an existing site. But you’ll still have a lot of work to do to reconcile your existing site content and structure with what has been created by the distribution. Here are a few tips to get you started–but you should begin with the assumption that there will be lots more you’ll discover and need to fix. Roles. Many distributions will create one or more custom roles. Examples include contributor, editor, and administrator. If any of these roughly correspond to existing roles on your site, delete the roles created by the distribution and rename the existing ones to use the distribution role names. For example, if your site has a role called “site administrator” and the distribution has created a role called “administrator”, delete the newly created “administrator” role and rename “site administrator” to “administrator”. After adjusting the role names, visit admin/config/people/accounts, ensure the “administrator” role is selected as the “Administrator role”, and save the form. Consolidating the roles in this way will get you the functionality of the distribution’s roles and permissions while maintaining your existing users’ role allocations.
If you already have a Drupal website that has a considerable amount of content or a large number of users or has custom functionality you want to keep, though, you might want to try directly upgrading the site to use the distribution. Doing so could save you a lot of time in migrating content. But it will also raise a number of challenges. Upgrading to a distribution is probably something you should try only if you have the skills and time needed to do troubleshooting and some custom data work.
There are several tips and best practices to follow to help you prepare for the upgrade. Still, since this is such a complex process, we highly recommend getting members of your development team involved from the beginning, which will help ensure the upgrade goes as smoothly as possible. Upgrading to Drupal 8 is more similar to building a new website than previous Drupal updates were, meaning that you should never perform the upgrade to Drupal 8 on a live site. It’s also strongly recommended that you create a backup of your live site so that if anything goes awry, you can quickly roll the site back to an earlier version while you figure out what the issue is. Read extra info at Drupal 8 Migration.