diff --git a/program/js/app.js b/program/js/app.js
index 5b9ee1db0..e72703f75 100644
--- a/program/js/app.js
+++ b/program/js/app.js
@@ -2530,7 +2530,7 @@ function rcube_webmail() {
                     html = '<span class="' + flags.attachmentClass + '" title="' + label + '"></span>';
                 } else if (flags.ctype == 'multipart/report') {
                     html = '<span class="report"></span>';
-                } else if (flags.ctype == 'multipart/encrypted' || flags.ctype == 'application/pkcs7-mime') {
+                } else if (flags.ctype == 'multipart/encrypted' || flags.ctype == 'application/pkcs7-mime' || flags.ctype == 'application/x-pkcs7-mime') {
                     html = '<span class="encrypted"></span>';
                 } else if (flags.hasattachment || (!flags.hasnoattachment && /application\/|multipart\/(m|signed)/.test(flags.ctype))) {
                     html = '<span class="attachment" title="' + label + '"></span>';
diff --git a/program/lib/Roundcube/rcube_message.php b/program/lib/Roundcube/rcube_message.php
index 249dc39a8..83f753c3e 100644
--- a/program/lib/Roundcube/rcube_message.php
+++ b/program/lib/Roundcube/rcube_message.php
@@ -892,7 +892,7 @@ class rcube_message
             }
         }
         // this is an S/MIME encrypted message -> create a plaintext body with the according message
-        elseif ($mimetype == 'application/pkcs7-mime') {
+        elseif ($mimetype == 'application/pkcs7-mime' || $mimetype == 'application/x-pkcs7-mime') {
             $p = new rcube_message_part();
             $p->type = 'content';
             $p->ctype_primary = 'text';