diff --git a/test-requirements.txt b/test-requirements.txt
index 517ca901..6670ec97 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -10,7 +10,7 @@ pytest-cov>=2.2.1,<=2.5.1                              # MIT
 # py.test plugin for generating HTML reports
 pytest-html>=1.10.0,<=1.15.1                           # Mozilla Public License 2.0 (MPL 2.0)
 # py.test xdist plugin for distributed testing and loop-on-failing modes
-pytest-xdist<=1.18.0                                   # MIT
+pytest-xdist<=1.15.0                                   # MIT
 
 coverage>=4.0,!=4.4,<=4.4.1                            # Apache License, Version 2.0
 ddt>=1.0.1,<=1.1.1