diff --git a/app/src/main/java/eu/faircode/email/ServiceSend.java b/app/src/main/java/eu/faircode/email/ServiceSend.java
index 55e0d677e8..728b652451 100644
--- a/app/src/main/java/eu/faircode/email/ServiceSend.java
+++ b/app/src/main/java/eu/faircode/email/ServiceSend.java
@@ -669,6 +669,10 @@ public class ServiceSend extends ServiceBase implements SharedPreferences.OnShar
             iservice.setUseIp(ident.use_ip, ident.ehlo);
             iservice.setUnicode(ident.unicode);
 
+            // 0=Read receipt
+            // 1=Delivery receipt
+            // 2=Read+delivery receipt
+
             if (message.receipt_request != null && message.receipt_request) {
                 int receipt_type = prefs.getInt("receipt_type", 2);
                 if (receipt_type == 1 || receipt_type == 2) // Delivery receipt