Preparing for Craft 4

Craft 4 is coming in 2022, and you can take steps right now that’ll make your sites easier to upgrade on launch day.

Craft 4 has been released! See Upgrading from Craft 3 in the documentation.

Update to the latest version of Craft 3. #

Craft 4 will require that you’re starting from 3.7.11+, so updating to the latest version will be important. This is especially true if you’ve got projects you need to upgrade from Craft 2.

Upgrade your environment. #

Craft 4 is going to require PHP 8.0.2+ and MySQL 5.7.8+ (or MariaDB 10.2.7+) or PostgreSQL 10+.

You can check if all your plugins are PHP 8-compatible by updating your platform config in composer.json:

  "config": {
    "platform": {
      "php": "8.0.2"

Then dry-run a composer update command:

composer update --dry-run

If the command is successful, you know you’re ready to upgrade your local and production servers to PHP 8.

The Intl and BCMath PHP extensions will also be required, so be sure those are installed.

Once everything’s upgraded, run composer update (without --dry-run this time) to pull in all the PHP 8-compatible dependencies.

Fix deprecation warnings. #

Thoroughly browse your site with the Debug Toolbar enabled (My AccountPreferencesShow the debug toolbar on the front end), and fix any deprecation warnings that are reported. You can also check UtilitiesDeprecation Warnings for a full list of recently-logged warnings.

What to look for:

You can make deprecation warnings especially hard to miss on your local environment by configuring Craft to throw exceptions rather than logging them. To do that, add this to config/app.php:

use craft\helpers\App;

return [
  'components' => [
    'deprecator' => [
      // Throw exceptions on deprecation warnings
      'throwExceptions' => App::parseBooleanEnv('$HARD_MODE') ?? false,

Then open up your local .env file and add a HARD_MODE environment variable:


Replace siteName and siteUrl config settings. #

The siteName and siteUrl config settings are being removed in Craft 4. To give your sites unique names/URLs for each environment, use environment variables instead.

Taking siteUrl, for example:

  1. Remove siteUrl from config/general.php.
  2. In the control panel, navigate to SettingsSites and add that previous value to Base URL.
  3. If you set the Base URL depending on the environment, create an environment variable in your site’s .env like $DEFAULT_SITE_URL=, adding $DEFAULT_SITE_URL as the Base URL field value.

Don’t forget to set any new environment variables in other environments, and your project’s .env.example if you use one!

No need to change the {{ siteUrl }} tag in your templates; it’s just the config setting that’s deprecated.

Prepare your templates for Twig 3. #

Craft 4 will update Twig from v2 to v3, which could require a few changes to your templates. Two things you can update right now:

  1. The {% spaceless %} tag is removed and now a filter instead. You can still use it as a tag pair via the apply tag:
     {% apply spaceless %}
       {# ... #}
     {% endapply %}
  2. The {% filter %} tag is removed. Use the {% apply %} tag instead.
  3. The {% for %} tag’s support for the if param is removed. Use |filter instead:
     {% for item in items|filter(item => item is not null) %}
       {# ... #}
     {% endfor %}

Replace GraphQL enabledForSite with status. #

The GraphQL API’s enabledForSite argument has been deprecated, which you can replace with status instead. enabledForSite accepted a boolean value and status accepts an array of the status strings you’ve seen throughout the Craft CMS control panel and PHP APIs—so it may not be as quick as a simple find and replace.

If you had been using enabledForSite as a query argument...

  entries(enabledForSite: true) {
} can replace that like this:

  entries(status: ["enabled"]) {

That’s already the default behavior, so it’s more likely you were fetching disabled entries:

  entries(enabledForSite: false) {

Doing the equivalent thing with status looks like this:

  entries(status: ["disabled"]) {

Applies to Craft CMS 4, Craft CMS 3, and Craft CMS 2.