diff --git a/setup.py b/setup.py
index 69b991c..db84fe2 100644
--- a/setup.py
+++ b/setup.py
@@ -24,7 +24,7 @@
         "scipy",
         "patsy",
         "statsmodels",
-        "protobuf==3.19",
+        "protobuf",
     ],
     setup_requires=["pytest-runner", "flake8"],
     tests_requires=["pytest"],