- I upgraded from Unity 4 to Unity 5
- I can no longer build my game to iOS/Android platforms
You have created a project using Unity 4 and build this scene for iOS/Android successfully in the UI system.
You have then upgraded to Unity 5 and when you load your project, you are not able to build to iOS/Android as the UI system is not working anymore.
The UI system in Unity 4 and 5 are slightly different. If you created a game in Unity 4, you can create a duplicate of the project for Unity 5.
If you were previously using assets from the Asset Store in your Unity 4 project you will need to completely remove these from the duplicate project and download the newest versions of each asset and re-import them into your Unity 5 project.
To update your purchased assets then see this article here.