How to force Appium tests running on iOS 8.1 iPhone 5s simulator

Hi, I’m using Appium 1.3.4, when I do the following config setup, my iPhone 8.1 tests will always run against iPhone 6… Can anyone please tell me how to force my tests running on iPhone 5S? Many thanks!

 "ios81": {
        "browserName": "",
        "platformName": "iOS",
        "platformVersion": "8.1",
        "deviceName": "iPhone Simulator",
        "app": ""

never mind… just figured it out… just change this - [“deviceName”: “iPhone 5s”]