From what I have seen and heard, upgrading to v4 will be a bit more work than from 3.5 to 3.6 - but not nearly as big as the v1->v2 transition. Here is a curre

From what I have seen and heard, upgrading to v4 will be a bit more work than from 3.5 to 3.6 - but not nearly as big as the v1->v2 transition. Here is a currently working link to a branch where this is developed (pre-alpha, so can change of course): https://github.com/ionic-team/ionic/tree/core/packages/ionic-angular https://github.com/ionic-team/ionic/tree/core/packages/ionic... & https://github.com/ionic-team/ionic/blob/core/packages/ionic-angular/BREAKING.md https://github.com/ionic-team/ionic/blob/core/packages/ionic... As I see it mostly the syntax and attributes of components were cleaned up. Ionic Framework is still fully based on Angular, it will just be using Custom Components (bundled in a package called @ionic/core) inside instead of the "Angular built Components" (no idea how to name these...) in v2+3. These custom components are built using the Stencil compiler by the Ionic team, but as a Ionic Framework user you won't (have to) come into contact with that at all. These new components can be used in other frameworks like React etc as well - or even AngularJS (Ionic v1!) or plain Javascript. An alpha of v4 is planned pretty soon I hear.