diff --git a/IPython/nbconvert/filters/markdown.py b/IPython/nbconvert/filters/markdown.py
index b36f336..cace686 100755
--- a/IPython/nbconvert/filters/markdown.py
+++ b/IPython/nbconvert/filters/markdown.py
@@ -77,7 +77,7 @@ class MathBlockGrammar(mistune.BlockGrammar):
 
 @undoc
 class MathBlockLexer(mistune.BlockLexer):
-    default_features = ['block_math', 'latex_environment'] + mistune.BlockLexer.default_features
+    default_rules = ['block_math', 'latex_environment'] + mistune.BlockLexer.default_rules
 
     def __init__(self, rules=None, **kwargs):
         if rules is None:
@@ -105,7 +105,7 @@ class MathInlineGrammar(mistune.InlineGrammar):
 
 @undoc
 class MathInlineLexer(mistune.InlineLexer):
-    default_features = ['math'] + mistune.InlineLexer.default_features
+    default_rules = ['math'] + mistune.InlineLexer.default_rules
 
     def __init__(self, renderer, rules=None, **kwargs):
         if rules is None:
@@ -124,10 +124,10 @@ class MarkdownWithMath(mistune.Markdown):
             kwargs['block'] = MathBlockLexer
         super(MarkdownWithMath, self).__init__(renderer, **kwargs)
 
-    def parse_block_math(self):
+    def output_block_math(self):
         return self.renderer.block_math(self.token['text'])
 
-    def parse_latex_environment(self):
+    def output_latex_environment(self):
         return self.renderer.latex_environment(self.token['name'], self.token['text'])
 
 @undoc