Convert Custom Ionic 3 Transitions to Ionic 4
Support for custom transitions between pages in Ionic framework (e.g. when opening a modal page) has never been well documented. Fortunately, there are blog posts for both Ionic 3 and Ionic 4 which provide more information and can serve as a good starting point for creating your own custom transitions. But even with all that, it can be tricky to convert existing custom Ionic 3 transitions to Ionic 4 when upgrading an application.