Avoid sending completely empty text parts for multipart/alternative m…

…essages (#5283)
roundcube · Jul 19, 2016 · f1d80c6 · f1d80c6
1 parent fbf8991
commit f1d80c6
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/program/steps/mail/sendmail.inc b/program/steps/mail/sendmail.inc
@@ -363,6 +363,11 @@ if ($isHtml) {
     $plainTextPart = rcube_mime::wordwrap($plainTextPart, $LINE_LENGTH, "\r\n", false, $message_charset);
     $plainTextPart = wordwrap($plainTextPart, 998, "\r\n", true);
 
+    // completely blank text part confuses some mail clients
+    if ($plainTextPart == '') {
+        $plainTextPart = "\r\n";
+    }
+
     // make sure all line endings are CRLF (#1486712)
     $plainTextPart = preg_replace('/\r?\n/', "\r\n", $plainTextPart);