diff --git a/doc/conf.py b/doc/conf.py
index 716aa7e90df0..0431f695e5e7 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -53,8 +53,7 @@
 
 autosummary_generate = True
 
-if sphinx.__version__ >= 1.1:
-    autodoc_docstring_signature = True
+autodoc_docstring_signature = True
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']