diff --git a/lib/html2text/lib.php b/lib/html2text/lib.php
index 8df48d6506d..18972d4c700 100644
--- a/lib/html2text/lib.php
+++ b/lib/html2text/lib.php
@@ -27,6 +27,7 @@
 defined('MOODLE_INTERNAL') || die();
 
 require_once($CFG->libdir . '/html2text/Html2Text.php');
+require_once(__DIR__ . '/override.php');
 
 /**
  * Wrapper for Html2Text
diff --git a/lib/html2text/override.php b/lib/html2text/override.php
new file mode 100644
index 00000000000..e7409458534
--- /dev/null
+++ b/lib/html2text/override.php
@@ -0,0 +1,58 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Wrapper for Html2Text
+ *
+ * This wrapper allows us to modify the upstream library without hacking it too much.
+ *
+ * @package    core
+ * @copyright  2015 Andrew Nicols <andrew@nicols.uk>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace Html2Text {
+    function mb_internal_encoding($encoding = null) {
+        static $internalencoding = 'utf-8';
+        if ($encoding !== null) {
+            $internalencoding = $encoding;
+            return true;
+        } else {
+            return $internalencoding;
+        }
+    }
+
+    function mb_substr($str, $start, $length, $encoding = null) {
+        if ($encoding === null) {
+            $encoding = mb_internal_encoding();
+        }
+        return \core_text::substr($str, $start, $length, $encoding);
+    }
+
+    function mb_strlen($str, $encoding = null) {
+        if ($encoding === null) {
+            $encoding = mb_internal_encoding();
+        }
+        return \core_text::strlen($str, $encoding);
+    }
+
+    function mb_strtolower($str, $encoding = null) {
+        if ($encoding === null) {
+            $encoding = mb_internal_encoding();
+        }
+        return \core_text::strtolower($str, $encoding);
+    }
+}