symfony - Fatal Error: composer.lock was created for PHP version 7.4 or higher but the current PHP version is 7.3.11

Question

I want to create a Symfony CRUD application. These are the steps I did:

• Downloaded and installed XAMPP from here with PHP 7.3.11 https://www.apachefriends.org/de/index.html
• Navigated to htdocs with the CLI of Windows.
• Created a symfony project with the command composer create-project symfony/skeleton my_project
• Opened up my browser (Firefox 70.0.1) and navigate to the URL: localhost/my_project/public/

Here I got the error message:

Fatal Error: composer.lock was created for PHP version 7.4 or higher but the current PHP version is 7.3.11.

When I check my php version in the CLI with php -v I get the result that I use PHP 7.4.0 (cli). When I check the php version by clicking the PHPInfo on the dashboard of XAMPP (localhost/dashboard/phpinfo.php), the page shows me the php version 7.3.11.

In the created symfony folder is a file called symfony.lock. There is an entry called "php": { "version": "7.4" },. Changing this entry did not solve my problem.

Any ideas how to solve this? And why I cannot install and test the newest symfony with XAMPP?

Thanks a lot guys!

Musa

Answer 1

This is thankfully quite easy to fix. You can tell your composer.json to install vendor libraries based on a specific version of PHP.

For instance we have a project currently in migration from PHP5 to PHP7. We cant install the PHP7 only versions of the libraries, so we add this to your composer.json:

  "config": {
    "platform": {
      "php": "5.3.29"
    }
  },

Now you should be able to install. Delete your composer.lock, then run composer install!

Here's the relevant documentation:

https://getcomposer.org/doc/06-config.md#platform