New features:
1. Support Dark Mode (iOS 13 only)
2. New drawing tool using PencilKit (iOS 13 only)
3. Support Multiple Windows (iOS 13 only)
4. Add caption to video
5. Add caption to audio
6. Rich Text Editor: add blockquote, indent and outdent
7. Scan document & extract text from document (iOS 13 only)
8. Custom text for Quiz
9. Optimized for iOS 13
10. Bug fix