If your Dynamics 365 instance is 9.0, it is time to ditch deprecated Dynamics 365 for Outlook (add-in) and switch to Dynamics 365 App for Outlook because version 9 is now out of preview.
Short summary of the new features and things you can do without leaving Outlook:
- Unified Interface
- View tracked email or appointment
- Quickly create entity records
- Search in Dynamics 365
- View Dynamics 365 records
Read more the full announcement on Dynamics 365 Customer Engagement Team Blog post.