Composer error: Could not parse version constraint >=~2

Friends, when trying to run the

composer update

the following error appears:

C:\wamp\www\mysystem>composer update Loading composer repositories with package information Updating dependencies (including require-dev)

[UnexpectedValueException] Could not parse version constraint

=~2: Invalid version string "~2"

update [--prefer-source] [--prefer-dist] [--dry-run] [--dev] [--no-dev] [--lock] [--no-custom-installers] [--no-autoloader] [--no-scripts] [--no-progress] [--no -suggest] [--with-dependencies] [-v|vv|vvv|--verbose] [-o|--optimize-autoloader] [-a|--classmap-authoritative] [--apcu-autoloader] [--ignore-platform-reqs] [--p refer-stable] [--prefer-lowest] [-i|--interactive] [--root-reqs] [--] [

]...

Here is my composer.json file:

{
    "license": "BSD-3-Clause",
    "minimum-stability": "stable",
    "require": {
        "php": ">=5.4.0",
        "yiisoft/yii2": ">=2.0.5",
        "yiisoft/yii2-bootstrap": "*",
        "yiisoft/yii2-swiftmailer": "*",
        "fxp/composer-asset-plugin": "~1.1.1",       
        "trntv/yii2-datetime-widget": "*",
        "miloschuman/yii2-highcharts-widget": "dev-master",
        "kartik-v/yii2-money": "*",
        "kartik-v/yii2-slider": "*",
        "kartik-v/yii2-widget-datepicker": "@dev",
        "kartik-v/yii2-field-range": "*",
        "kartik-v/yii2-widget-colorinput": "*",
        "kartik-v/yii2-widget-sidenav": "@dev",
        "kartik-v/yii2-export": "@dev",
        "kartik-v/yii2-grid": "@dev",
        "yiidoc/yii2-redactor": "*",
        "tugmaks/yii2-google-maps": "dev-master",
        "yiisoft/yii2-imagine": "^2.0",
        "karpoff/yii2-crop-image-upload": "*",
        "cyneek/yii2-menu": "dev-master",
        "bupy7/yii2-widget-cropbox": "*",
        "philippfrenzel/yii2fullcalendar": "*",
        "kartik-v/yii2-widget-touchspin": "*"
    },
    "require-dev": {
        "yiisoft/yii2-debug": "*",
        "yiisoft/yii2-gii": "*",
        "yiisoft/yii2-faker": "*"
    },
    "config": {
        "process-timeout": 1800
    },
    "scripts": {
        "post-create-project-cmd": [
            "yii\\composer\\Installer::postCreateProject"
        ]
    },
    "extra": {
        "yii\\composer\\Installer::postCreateProject": {
            "setPermission": [
                {
                    "runtime": "0777",
                    "web/assets": "0777",
                    "yii": "0755"
                }
            ],
            "generateCookieValidationKey": [
                "config/web.php"
            ]
        },
        "asset-installer-paths": {
            "npm-asset-library": "vendor/npm",
            "bower-asset-library": "vendor/bower"
        }
    }
}

I tried on w7 and ubuntu