Flutter OneSignal Push Notifications Debugging

I'm facing issues with the integration of OneSignal push notifications into my Flutter app. It was working on an older version but since have updated my project and it will not compile anymore. I need someone to help on a screen share fix 5-7 different pages of code where Onesignal is implmented. For reference it was moved from version 3.5 up to 5
I can not send the code it will have to be on a screen share. I need the application to run both on my android and ios emulators before it is considered complete.