Laravel Composer 看到错误的 PHP 版本

I'm trying to install an older Laravel Project.

When I run composer install I get the following error

This package requires php >=5.6.4 but your PHP version (5.5.35) does not satisfy that requirement.

When I run

php -v

I get the following result

PHP 7.1.10 (cli) (built: Oct 12 2017 14:00:12) ( ZTS )

This is the content of my composer.json

{
    "name": "laravel/laravel",
    "description": "The Laravel Framework.",
    "keywords": ["framework", "laravel"],
    "license": "MIT",
    "type": "project",
    "require": {
        "php": ">=5.6.4",
        "doctrine/dbal": "^2.6",
        "guzzlehttp/guzzle": "^6.3",
        "intervention/image": "^2.4",
        "intervention/imagecache": "^2.3",
        "laravel/framework": "5.4.*",
        "laravel/tinker": "~1.0",
        "laravelcollective/html": "^5.4",
        "maatwebsite/excel": "^2.1",
        "sentry/sentry-laravel": "^0.8.0",
        "spatie/laravel-glide": "^3.2",
        "spatie/laravel-permission": "^2.6",
        "spatie/laravel-pjax": "^1.3"
    },
    "require-dev": {
        "fzaninotto/faker": "~1.4",
        "mockery/mockery": "0.9.*",
        "phpunit/phpunit": "~5.7"
    },
    "autoload": {
        "classmap": [
            "database"
        ],
        "psr-4": {
            "App\": "app/"
        }
    },
    "autoload-dev": {
        "psr-4": {
            "Tests\": "tests/"
        }
    },
    "scripts": {
        "post-root-package-install": [
            "php -r "file_exists('.env') || copy('.env.example', '.env');""
        ],
        "post-create-project-cmd": [
            "php artisan key:generate"
        ],
        "post-install-cmd": [
            "Illuminate\Foundation\ComposerScripts::postInstall",
            "php artisan optimize"
        ],
        "post-update-cmd": [
            "Illuminate\Foundation\ComposerScripts::postUpdate",
            "php artisan optimize"
        ]
    },
    "config": {
        "preferred-install": "dist",
        "sort-packages": true,
        "optimize-autoloader": true
    }
}

How is it possible that this project thinks I have php 5.6 running?

Thank you.

解决方案

I've had this problem too. If you don't want to update all your composer packages, you can solve this issue by manually changing the composer.lock file and writing your actual PHP version in platform > php in the JSON object.

Example

...
"platform": {
    "php": "7.1"
}
...

Although it works, the most recommended way to do this would be deleting your composer.lock file, changing the platform > php version in composer.json and then executing composer install.