3. Upgrade the app

At this point, you should have a composer.json file with the correct requirements. Run composer update to update the dependencies. 

composer update

If you want to first test how the update proceeds without actually updating any packages, you can try the command with the --dry-run switch:

composer update --dry-run

Upgrading packages

If your application consists of several packages that are placed in locations other than the src/ folder, apply the suggestions from the upgrade documentation to all the packages before you run composer update.

Common errors

If you experience issues during the update, such as a cloning failure, see the Common errors section on the Composer about page.