Can Ionic Native 2.x be used with Ionic 3.x?

Imagine you invested lots of time to get Ionic Native 2.x stuff implemented in your app, also in ways that are maybe not standard. Is this a blocker for upgrading to Ionic 3.x or can you safely continue using Ionic Native 2.x while upgrading to Ionic 3.x?

(Yes, I’m aware why Ionic Native 3.x might be better - but I’m trying to limit the scope of the upgrade to Ionic 3.x here.)