diff --git a/setup.py b/setup.py
index 750c467..55100a3 100644
--- a/setup.py
+++ b/setup.py
@@ -28,8 +28,8 @@
 # 'Development Status :: 5 - Production/Stable'
 release_status = "Development Status :: 5 - Production/Stable"
 dependencies = [
-    "google-api-core >= 1.21.0, < 3.0.0dev",
-    "google-auth >= 1.24.0, < 3.0dev",
+    "google-api-core >= 1.31.5, <3.0.0dev,!=2.0.*,!=2.1.*,!=2.2.*,!=2.3.0",
+    "google-auth >= 1.25.0, < 3.0dev",
 ]
 extras = {"grpc": "grpcio >= 1.8.2, < 2.0dev"}
 
diff --git a/testing/constraints-3.6.txt b/testing/constraints-3.6.txt
index bc4f7d2..8b2701c 100644
--- a/testing/constraints-3.6.txt
+++ b/testing/constraints-3.6.txt
@@ -5,6 +5,6 @@
 #
 # e.g., if setup.py has "foo >= 1.14.0, < 2.0.0dev",
 # Then this file should have foo==1.14.0
-google-api-core==1.21.0
-google-auth==1.24.0
+google-api-core==1.31.5
+google-auth==1.25.0
 grpcio==1.8.2