diff --git a/Makefile b/Makefile
index f29fa5923..4ca2743a8 100644
--- a/Makefile
+++ b/Makefile
@@ -21,6 +21,7 @@ deploy:
 	@$(SPHINXBUILD) -M html "$(SOURCEDIR)" "$(BUILDDIR)" -nW
 	#  -n   Run in nit-picky mode. Currently, this generates warnings for all missing references.
 	#  -W   Turn warnings into errors that stop the build.
+	# for more details about the options see https://www.sphinx-doc.org/en/1.8/man/sphinx-build.html#options
 
 # Catch-all target: route all unknown targets to Sphinx using the new
 # "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
diff --git a/requirements.txt b/requirements.txt
index 8ce08cf12..08ea1c6ab 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,3 @@
-Sphinx==1.7.1
+Sphinx==1.8.5
 sphinx-rtd-theme==0.2.4
 sphinx-autobuild==0.7.1
\ No newline at end of file