diff --git a/app/src/main/java/eu/faircode/email/MessageHelper.java b/app/src/main/java/eu/faircode/email/MessageHelper.java
index abe1d856ff..5b432fd033 100644
--- a/app/src/main/java/eu/faircode/email/MessageHelper.java
+++ b/app/src/main/java/eu/faircode/email/MessageHelper.java
@@ -95,10 +95,10 @@ public class MessageHelper {
         System.setProperty("mail.mime.cachemultipart", "false");
 
         // https://docs.oracle.com/javaee/6/api/javax/mail/internet/MimeMultipart.html
-        System.setProperty("mail.mime.multipart.ignoremissingboundaryparameter", "true"); // javax.mail.internet.ParseException: In parameter list
-        System.setProperty("mail.mime.multipart.ignoreexistingboundaryparameter", "true");
-        System.setProperty("mail.mime.multipart.ignoremissingendboundary", "true");
-        System.setProperty("mail.mime.multipart.allowempty", "true");
+        System.setProperty("mail.mime.multipart.ignoremissingboundaryparameter", "true"); // default true, javax.mail.internet.ParseException: In parameter list
+        System.setProperty("mail.mime.multipart.ignoreexistingboundaryparameter", "true"); // default false
+        System.setProperty("mail.mime.multipart.ignoremissingendboundary", "true"); // default true
+        System.setProperty("mail.mime.multipart.allowempty", "true"); // default false
     }
 
     static Properties getSessionProperties() {