diff --git a/ci_scripts/circle_install.sh b/ci_scripts/circle_install.sh
index a54ddd922c..fc4d372f81 100644
--- a/ci_scripts/circle_install.sh
+++ b/ci_scripts/circle_install.sh
@@ -8,7 +8,7 @@ source activate testenv
 
 # install documentation building dependencies
 pip install --upgrade numpy
-pip install --upgrade matplotlib setuptools nose coverage sphinx pillow sphinx-gallery sphinx_bootstrap_theme cython numpydoc
+pip install --upgrade matplotlib setuptools nose coverage sphinx==1.5.5 sphinx_bootstrap_theme numpydoc
 # And finally, all other dependencies
 cat requirements.txt | xargs -n 1 -L 1 pip install
 
diff --git a/doc/manual.rst b/doc/manual.rst
index d21bb1412a..de89376979 100644
--- a/doc/manual.rst
+++ b/doc/manual.rst
@@ -68,7 +68,7 @@ For a full list please have a look at the source code (in `autosklearn/pipeline/
   * `Preprocessors <https://github.com/automl/auto-sklearn/tree/master/autosklearn/pipeline/components/feature_preprocessing>`_
 
 Turning off preprocessing
-~~~~~~~~~~~~~~~~~~~~~~~~
+~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Preprocessing in *auto-sklearn* is divided into data preprocessing and
 feature preprocessing. Data preprocessing includes One-Hot encoding of