diff --git a/docs/source/requirements.txt b/docs/source/requirements.txt
deleted file mode 100644
index 67768efd5..000000000
--- a/docs/source/requirements.txt
+++ /dev/null
@@ -1,4 +0,0 @@
-# pinning sphinx to 1.4.* due to search issues with rtd:
-# https://github.com/rtfd/readthedocs-sphinx-ext/issues/25
-# https://github.com/rtfd/readthedocs.org/issues/2708
-sphinx ==1.4.*