diff --git a/CHANGELOG b/CHANGELOG
index 0a61ef54e..448307fef 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,6 +1,8 @@
 CHANGELOG Roundcube Webmail
 ===========================
 
+- Fix so exported vCard specifies encoding in v3-compatible format (#1489183)
+
 RELEASE 0.9.2
 -------------
 - Fix image thumbnails display in print mode (#1489134)
diff --git a/program/lib/Roundcube/rcube_vcard.php b/program/lib/Roundcube/rcube_vcard.php
index aded4aa78..285dc29a1 100644
--- a/program/lib/Roundcube/rcube_vcard.php
+++ b/program/lib/Roundcube/rcube_vcard.php
@@ -714,9 +714,15 @@ class rcube_vcard
                             $value[] = $attrvalues;
                         }
                         else if (is_bool($attrvalues)) {
-                            // true means just tag, not tag=value, as in PHOTO;BASE64:...
+                            // true means just a tag, not tag=value, as in PHOTO;BASE64:...
                             if ($attrvalues) {
-                                $attr .= strtoupper(";$attrname");
+                                // vCard v3 uses ENCODING=B (#1489183)
+                                if ($attrname == 'base64') {
+                                    $attr .= ";ENCODING=B";
+                                }
+                                else {
+                                    $attr .= strtoupper(";$attrname");
+                                }
                             }
                         }
                         else {