My upgrade is failing. I am at 8.9.19 and I used upgrade-status to make sure all my modules are compatible with next major core version. I am following instructions at https://www.drupal.org/docs/upgrading-drupal/upgrading-from-drupal-8-to-drupal-9-or-later

When I get to step 3, running composer update, I'm getting a slew of problems of the form

- drupal/core-recommended 9.0.0 requires drupal/core 9.0.0 -> found drupal/core[9.0.0] but it conflicts with your root composer.json require (^8.9.19)

mentioning all 9.x versions. I can post my entire composer.json if that will help, but I think these are the relevant lines:

        "drupal/core": "^8.9.19",
        "drupal/core-composer-scaffold": "^9",
        "drupal/core-project-message": "^9",
        "drupal/core-recommended": "^9",
    "require-dev": {
        "drupal/core-dev": "^9"

I had originally created the project with

composer create-project drupal-composer/drupal-project:8.x-dev www --stability dev --no-interaction

Any suggestions, or pointers to a different tutorial on upgrading, would be greatly appreciated.

  • 1
    I think you need to remove the line "drupal/core": "^8.9.19", from your composer.json. Maybe also refer to drupal.org/docs/updating-drupal/… for updating drupal using composer, which highlights the difference between using drupal/core and drupal/core-recommended. The latter is the, well, recommended way at the moment.
    – berliner
    Commented Nov 7, 2021 at 0:36
  • 1
    Yes. There is no need for that when you have core-recommended.
    – Kevin
    Commented Nov 7, 2021 at 0:38
  • Thanks - I removed "drupal/core": "^8.9.19" and the previous errors went away, but I don't know what to make of these new ones; they are all similar to the last one: - Conclusion: don't install symfony/var-dumper v5.3.10 (conflict analysis result) - Root composer.json requires drupal/core-recommended ^9 -> satisfiable by drupal/core-recommended[9.0.0-alpha1, ..., 9.4.x-dev]
    – pglatz
    Commented Nov 7, 2021 at 0:46
  • symfony/var-dumper is not in my composer.json -- aha, I found it in vendor/symfony/var-dumper/composer.json -- what is the correct way to remove this redpendency? Blow away the whole directory?
    – pglatz
    Commented Nov 7, 2021 at 2:52
  • Does this answer your question? How do I fix a var-dumper conflict?
    – leymannx
    Commented Nov 7, 2021 at 21:23

1 Answer 1


Solved, I had to remove the drupal/core package from the composer.json and update the Devel module to fix a conflict with symfony/var-dumper.

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