1) Appium 1.6.0 beta1 Installation

I have managed to run my IOS tests on XCUItest using below changes.
Elements have to migrated from UIA to XCUI elements

Inorder to run appium on 1.6.0 beta 1 for ios 10 and xcode 8
use below settings

[caps]
platformName = "iOS"
orientation = "PORTRAIT"
platformVersion = "10.0"
deviceName ="iPhone Simulator"
noReset = "false"
automationName = "xcuitest"
appiumVersion = "1.6.0-beta1"
app="<app_path>/<app_name>.app"
[appium_lib]

Installation

npm uninstall appium
npm install appium@1.6.0-beta1

npm install -g appium-xcuitest-driver

brew install carthage

Install carthage dependency manager

Error : Fetching dependencies\nPlease make sure that you have Carthage installed (https://github.com/Carthage/Carthage)\nNote: We are expecting that carthage installed in /usr/local/bin/\n',
Solution : brew install carthage

Xcode 8 Installation : 

download xcode

unzip the xcode file 

Rename old /Applications/Xcode.app to /Applications/Xcode7.app(incase you still want to keep it)

Drag new Xcode app to /Applications/Xcode.app

Open Xcode and install it 

Other fixes: 

If you encounter issues  check here - https://github.com/appium/appium/issues/6853

I had to manually run bootstrap as mentioned in above link 

cd ~/.npm-global/lib/node_modules/appium-xcuitest-driver/WebDriverAgent

sh Scripts/bootstrap.sh 

To Properly install node check this link - https://github.com/sindresorhus/guides/blob/master/npm-global-without-sudo.md