diff --git a/docs/conf.py b/docs/conf.py
index 09bb44285..2e6c5a9b7 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -40,6 +40,7 @@ needs_sphinx = '1.0'
 # ones.
 extensions = [
     'sphinx.ext.autodoc',
+    'sphinx.ext.imgconverter',
     'sphinx.ext.intersphinx',
     'sphinx.ext.todo',
     'sphinx.ext.coverage',
diff --git a/setup.py b/setup.py
index 1827c4d42..a13b7cdb9 100644
--- a/setup.py
+++ b/setup.py
@@ -70,8 +70,8 @@ dev3_extras = [
 
 docs_extras = [
     'repoze.sphinx.autointerface',
-    # autodoc_member_order = 'bysource', autodoc_default_flags, and #4686
-    'Sphinx >=1.0,<=1.5.6',
+    # sphinx.ext.imgconverter
+    'Sphinx >=1.6',
     'sphinx_rtd_theme',
 ]
 
diff --git a/tools/dev_constraints.txt b/tools/dev_constraints.txt
index f14169bfc..ef7804328 100644
--- a/tools/dev_constraints.txt
+++ b/tools/dev_constraints.txt
@@ -60,8 +60,9 @@ s3transfer==0.1.11
 scandir==1.6
 simplegeneric==0.8.1
 snowballstemmer==1.2.1
-Sphinx==1.5.6
+Sphinx==1.7.5
 sphinx-rtd-theme==0.2.4
+sphinxcontrib-websupport==1.0.1
 tldextract==2.2.0
 tox==2.9.1
 tqdm==4.19.4