Preparing to upgrade ionic and other libraries -any best practices?

Hi there, I have a production app in the App Store (zminja-pro) that uses ionic. Its based on a fairly old version

Cordova CLI: 5.3.1
Gulp version:  CLI version 3.9.1
Gulp local:  
Ionic CLI Version: 1.7.0
Ionic App Lib Version: 0.5.1-beta.0
ios-deploy version: Not installed
ios-sim version: 5.0.2 
OS: Mac OS X El Capitan
Node Version: v0.12.4
Xcode version: Xcode 7.3 Build version 7D175 

Are there any best practices to upgrade ? I don’t want to reach a situation where everything breaks and I can’t revert.

Specifically, people who tried to compile my code using Cordova 6 have reported it sucks up all memory and doesn’t start - maybe its a plugin issue which they did not upgrade - don’t know. So I want to be cautious

Also, a few months ago ionic folks had reported of various breakages with IOS 9, namely and – does anyone know if more recent version have fixes for them ?