diff --git a/examples/tutorials/6. Flexible outputs specification.ipynb b/examples/tutorials/6. Flexible outputs specification.ipynb
index c1fc84b..5a1ba1d 100644
--- a/examples/tutorials/6. Flexible outputs specification.ipynb	
+++ b/examples/tutorials/6. Flexible outputs specification.ipynb	
@@ -432,7 +432,7 @@
    ],
    "source": [
     "output_spec = [\n",
-    "    'sklearn.impute.SimpleImputer#1.X',\n",
+    "    # 'sklearn.impute.SimpleImputer#1.X',\n",
     "    'mlprimitives.custom.preprocessing.ClassEncoder#1.y',\n",
     "    'mlprimitives.custom.preprocessing.ClassEncoder#1.classes',\n",
     "]\n",
diff --git a/setup.py b/setup.py
index 850b8d0..e54291b 100644
--- a/setup.py
+++ b/setup.py
@@ -53,11 +53,10 @@
     'watchdog>=0.8.3,<5',
 
     # docs
-    'm2r>=0.2.0,<0.3',
+    'm2r2>=0.2.5,<0.3',
     'Sphinx>=1.7.1,<3',
     'sphinx_rtd_theme>=0.2.4,<0.5',
     'docutils>=0.12,<0.18',
-    'lxml_html_clean>=0.2.2',
     'ipython>=6.5.0',
     'autodocsumm>=0.1.10',
     'Jinja2>=2,<3', # >=3 makes sphinx theme fail