External Users Now See Case Emails in the Feed

When you enable the community case feed, case emails appear in the community case feed for external users who have access to the case. Case emails in the feed list the email’s author, recipients, text, and time sent.
Available in: Enterprise, Performance, Unlimited, and Developer Editions

If the case contact is the email author or recipient, the email is visible in the case feed for all users who are associated with the case, including external users. However, emails between agents aren’t visible to external users.
Note

Note

For an external user to view the case, their profile must include access to cases in the community.

Suppose Rita, an external user, posts a question in a community. The question remains unresolved, and a community moderator creates a case from it using the Question-to-Case action. If the support agent assigned to the case emails Rita from the email publisher, Rita and all other users with access to the case will see the email in their case feed. Users with access include the assigned support agent, case contact, and any partners.

You can write an Apex trigger to set the visibility of case emails to external users who have access to the case, regardless of whether you’ve enabled the community case feed. The IsExternallyVisible field of the EmailMessage object controls the visibility of email messages. When the field is set to true—its default value—email messages are visible to external users. To hide case emails from external users, write a trigger that sets the IsExternallyVisible field to false when an email message is created.