True or False: Notifications Sets can only be customized in HTML format.

The correct answer is that it is false that Notification Sets can only be customized in HTML format. Mimecast allows flexibility in how notifications are presented, enabling customization in various formats beyond just HTML. This includes options such as plain text, which can be useful for different contexts or user preferences. Being able to customize notifications in multiple formats enhances the versatility of the Mimecast system for different environments.

The availability of more than one format for Notification Sets is crucial for ensuring compatibility with various email clients and user needs, allowing users to choose the format that best suits their requirements. This is particularly important in maintaining accessibility and ensuring that all users can effectively receive and interpret notifications.

Hence, the statement that customization is limited solely to HTML is inaccurate, as Mimecast supports multiple formats for notifications.