First, we'll identify the considerations to factor in.

Although there are a number of core Drupal tools and contributed modules to help with the technical aspects of migration, you'll need a structure and framework to successfully plan and deliver the migration project.

At Strange, we break the project down into four phases;

Find out more

Improve your website performance with Drupal

1. Current state assessment

Understanding the level of customisation of your site and the data it contains is the key to success. The items required to fully assess the level of customisation are listed below:

  • The modules installed, whether they are vital or even used, together with their version number
  • The theme used, whether custom developed, from a theme provider (non modified), or heavily modified theme, version number
  • The extent of any modifications to these extensions and theme
  • How have modifications been managed and are there strong version control procedures in place and have modifications been completed according to accepted Drupal development standards?
  • The extent and nature of any integrations to third party systems (API and non API based)
  • Documentation and understanding of DevOps and the hosting environment
  • Skill, ability and availability of associated development resources related to migration from Drupal 7 or Drupal 8

2. Target state assessment

Defining the target state of your new Drupal 9 website is much easier if the current state has been detailed and accurately recorded.

Time to review functionality?

Migrating to Drupal 9 is also a good opportunity to review website functionality, UX and creative. It’s also a good time to assess whether you have access to the skills and capabilities to take your website forward.

Modules, themes and custom code

There are Drupal 7 modules that are not (currently) available on Drupal 9. This is a significant barrier to upgrade for many site owners so care and attention is needed when evaluating the upgrade path.

To help with Drupal 9 migration projects, Drupal Core has the following migration tools available;

  • Migrate
  • Migrate Drupal
  • Migrate Drupal UI

And there are several contributed modules also available;

  • Drupal Upgrade
  • Migrate Tools
  • Migrate Plus
  • Migrate Manifest
  • Migrate UI


Content migration is a relatively simple process and well supported with core modules.

API and integrations

API migrations can take considerable development effort, depending on the extent of integrations. Drupal 8’s new architecture may well result in a different approach, and from a planning perspective it is worth separating out this activity into a distinct work stream.

Hosting and DevOps

Don’t forget to include DevOps and associated hosting work in the target state assessment.

Your hosting environment may also need to be reviewed. Making sure you select an appropriate PHP version is also an important consideration.

Like to know more?

Ask us about how Drupal could work for you.

3. Gap analysis

Having defined the current and target states, we define the best approach to either migrate functionality or rebuild functionality.

This is the ideal time to consider additional development, creative, and functional enhancements. It make no sense to replicate bad functionality!

4. Project delivery

Thorough and well executed planning makes the delivery phase relatively routine and predictable.

Whether you choose to upgrade to Drupal 9 using your internal team, via your existing agency, or whether you're considering changing agencies, upgrading to Drupal 9 is now time critical.


Ask us anything about Drupal

Related Drupal Services