Issue with Outlook displaying calendar invite attachment as inline

Hello,

I am having an issue with the Drupal Mandrill module. I am using the module to send calendar invites to users via email. The invites are sent as an attachment with the "text/calendar" MIME type. While Gmail displays the invite inline with the email, Outlook displays it as an attachment, making it less convenient for the users.

I have tried setting the "Content-Disposition" header to "inline" in the attachment, but that did not solve the issue.

Could you please advise on how to fix this issue or if there is a workaround to display the invite inline with the email in Outlook?

Thank you.