diff --git a/setup.py b/setup.py
index 29a3757..08e0fd9 100644
--- a/setup.py
+++ b/setup.py
@@ -34,7 +34,7 @@
       include_package_data=True,
       zip_safe=True,
       install_requires=[
-        "pymongo[encryption]",
+        "pymongo[encryption]<4.9",
         "pytz",
       ],
       tests_require=[