diff --git a/requirements.txt b/requirements.txt
index 73c32d1f..36aed5f9 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,5 +3,6 @@ defusedxml
 packaging
 future; python_version < "3.0"
 ujson<3; python_version < "3.0"
+ujson<4; python_version >= "3.5" and python_version < "3.6"
 ujson<5; python_version >= "3.6" and python_version < "3.7"
 ujson; python_version >= "3.7"