Ionic mobile app upgrade

Hi all Before I bore you with the technicalities, let me tell you what I am looking to achieve: I am looking to make some updates on my existing app My app has been developed on Ionic CLI 3.2 I want to now make a few changes and when I run source code via ionic serve, I am getting too many errors. It is asking me to update ionic CLI to Version 6. The system is also not allowing me to install an older version of the node as the node version was 5.x when I first developed this app and right now that seems to be old. If I try to use a newer version of the node then the app throws so many errors with the most common error being ‘app-script’ and many others. When the app was originally built the system was configured as below Node - 5.8.0 Ionic Framework - 3 Ionic CLI - 3.2.0 Ideally what I am looking to do is update the app with the latest framework along with updating the other npm packages which also need updating with the latest SDK (as I heard apple will soon be requiring their members to update this in June). Now I am trying to achieve all the latest versions but with the current app. Most probably the npm packages. If we use the latest npm then all its packages get updated that will cause to update their syntax and other things related to this, for example, FCM to perform a push notification. So this is the task