diff --git a/helpdesk/models.py b/helpdesk/models.py
index 7ef1b9c9..6a20091d 100644
--- a/helpdesk/models.py
+++ b/helpdesk/models.py
@@ -50,9 +50,9 @@ def format_time_spent(time_spent):
 
 
 class EscapeHtml(Extension):
-    def extendMarkdown(self, md, md_globals):
-        del md.preprocessors['html_block']
-        del md.inlinePatterns['html']
+    def extendMarkdown(self, md):
+        md.preprocessors.deregister('html_block')
+        md.inlinePatterns.deregister('html')
 
 
 def get_markdown(text):
diff --git a/helpdesk/tests/test_markdown.py b/helpdesk/tests/test_markdown.py
index edfb4dbd..7eeccb02 100644
--- a/helpdesk/tests/test_markdown.py
+++ b/helpdesk/tests/test_markdown.py
@@ -20,14 +20,14 @@ class MarkDown(SimpleTestCase):
         self.assertEqual(output_value, expected_value)
 
     def test_markdown_fenced_code(self):
-        expected_value = '<h1>Title</h1>\n<pre><code class="python"># import os\n</code></pre>'
+        expected_value = '<h1>Title</h1>\n<pre><code class="language-python"># import os\n</code></pre>'
         input_value = """
 # Title
 
 ```python
 # import os
 ```
-        """        
+        """
         output_value = get_markdown(input_value)
         self.assertEqual(output_value, expected_value)
 
diff --git a/requirements.txt b/requirements.txt
index 3647bb5e..5093ae89 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,7 +3,7 @@ django-bootstrap4-form
 celery
 email-reply-parser
 akismet
-markdown<3.0
+markdown
 beautifulsoup4
 lxml
 simplejson