In the context of a SaaS application, identify which two of the following features are on-platform retention enhancement levers:
- Feature I: Customizable user dashboards that display data relevant to specific user roles and preferences.
- Feature II: Regular email newsletters updating users about new features and tips.
- Feature III: Machine learning algorithms that tailor the user interface and functionalities based on user behavior.
- Feature IV: External integrations with other widely used business tools to streamline workflows.