diff --git a/src/headerdef.rs b/src/headerdef.rs
index c899ac57f..28fb4877d 100644
--- a/src/headerdef.rs
+++ b/src/headerdef.rs
@@ -11,11 +11,20 @@ pub enum HeaderDef {
     To,
     Cc,
     Disposition,
+
+    /// Used in the "Body Part Header" of MDNs as of RFC 8098.
+    /// Indicates the Message-ID of the message for which the MDN is being issued.
     OriginalMessageId,
 
     /// Delta Chat extension for message IDs in combined MDNs
     AdditionalMessageIds,
 
+    /// Outlook-SMTP-server replace the `Message-ID:`-header
+    /// and write the original ID to `X-Microsoft-Original-Message-ID`.
+    /// To sort things correctly and to not show outgoing messages twice,
+    /// we need to check that header as well.
+    XMicrosoftOriginalMessageId,
+
     ListId,
     References,
     InReplyTo,
diff --git a/src/mimefactory.rs b/src/mimefactory.rs
index b89e981fd..06d8a6973 100644
--- a/src/mimefactory.rs
+++ b/src/mimefactory.rs
@@ -514,12 +514,6 @@ impl<'a> MimeFactory<'a> {
             ));
         }
 
-        // we could also store the message-id in the protected headers
-        // which would probably help to survive providers like
-        // Outlook.com or hotmail which mangle the Message-ID.
-        // but they also strip the Autocrypt header so we probably
-        // never get a chance to tunnel our protected headers in a
-        // cryptographic payload.
         unprotected_headers.push(Header::new(
             "Message-ID".into(),
             render_rfc724_mid(&rfc724_mid),
diff --git a/src/mimeparser.rs b/src/mimeparser.rs
index 93966bd60..dfe3d4986 100644
--- a/src/mimeparser.rs
+++ b/src/mimeparser.rs
@@ -950,7 +950,8 @@ impl MimeMessage {
     }
 
     pub fn get_rfc724_mid(&self) -> Option<String> {
-        self.get(HeaderDef::MessageId)
+        self.get(HeaderDef::XMicrosoftOriginalMessageId)
+            .or_else(|| self.get(HeaderDef::MessageId))
             .and_then(|msgid| parse_message_id(msgid).ok())
     }
 
@@ -2749,4 +2750,27 @@ On 2020-10-25, Bob wrote:
             "mime-modified test – mime-modified *set*; simplify is always regarded as lossy."
         );
     }
+
+    #[async_std::test]
+    async fn test_x_microsoft_original_message_id() {
+        let t = TestContext::new().await;
+        let message = MimeMessage::from_bytes(&t, b"Date: Wed, 17 Feb 2021 15:45:15 +0000\n\
+                Chat-Version: 1.0\n\
+                Message-ID: <DBAPR03MB1180CE51A1BFE265BD018D4790869@DBAPR03MB6691.eurprd03.prod.outlook.com>\n\
+                To: Bob <bob@example.org>\n\
+                From: Alice <alice@example.org>\n\
+                Subject: Message from Alice\n\
+                Content-Type: text/plain\n\
+                X-Microsoft-Original-Message-ID: <Mr.6Dx7ITn4w38.n9j7epIcuQI@outlook.com>\n\
+                MIME-Version: 1.0\n\
+                \n\
+                Does it work with outlook now?\n\
+                ")
+            .await
+            .unwrap();
+        assert_eq!(
+            message.get_rfc724_mid(),
+            Some("Mr.6Dx7ITn4w38.n9j7epIcuQI@outlook.com".to_string())
+        );
+    }
 }