diff --git a/app/src/main/java/eu/faircode/email/MessageHelper.java b/app/src/main/java/eu/faircode/email/MessageHelper.java
index 89af5710a8..6a5993cb80 100644
--- a/app/src/main/java/eu/faircode/email/MessageHelper.java
+++ b/app/src/main/java/eu/faircode/email/MessageHelper.java
@@ -208,7 +208,8 @@ public class MessageHelper {
             "$signed", // Kmail
             "$encrypted", // Kmail
             "$HasAttachment", // Dovecot
-            "$HasNoAttachment" // Dovecot
+            "$HasNoAttachment", // Dovecot
+            "$IsTrusted" // Fastmail
     ));
 
     // https://tools.ietf.org/html/rfc4021