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/

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