What does this mean? npm WARN deprecated es5-shim@2.3.0

I am setting up a development environment and I ran into a little issue (i guess).

When I run npm install, it takes all the dependencies specified in the package.js and installs them, as far as I know.

But for some reason whenever I execute that command I get :

npm WARN deprecated es5-shim@2.3.0: Please update to the latest version; it over rides noncompliant native methods even in modern implementations

Well I have no idea what this message means, so I hope maybe someone can help.

This is my package.js :

{
    "name":"recapday",
    "repository": {
    "type": "git",
    "url": "git://github.com/magestican/Recapday-UI.git"
    },
    "version": "0.1.0",
    "devDependencies":{
        "express": "~4.8.5",
        "grunt": "~0.4.5",
        "grunt-angular-templates": "~0.5.7",
        "grunt-browserify": "~1.2.11",
        "grunt-contrib-watch": "~0.6.1",
        "grunt-contrib-concat": "~0.3.0",
        "grunt-contrib-uglify": "~0.5.1",
        "grunt-contrib-jasmine": "~0.7.0",
        "grunt-contrib-sass": "~0.8.0",
        "grunt-exec": "~0.4.6",
        "grunt-contrib-less": "~0.11.4"
    }
}