diff --git a/src/php/tests/generated_code/AbstractGeneratedCodeTest.php b/src/php/tests/generated_code/AbstractGeneratedCodeTest.php
index 29dbe1975cf85e4f2b6d177be2d4d0a2b5416ba6..c50b1c6943e9236beb31ba1fc9ee2d5e1309c276 100644
--- a/src/php/tests/generated_code/AbstractGeneratedCodeTest.php
+++ b/src/php/tests/generated_code/AbstractGeneratedCodeTest.php
@@ -32,6 +32,9 @@
  *
  */
 require_once realpath(dirname(__FILE__).'/../../vendor/autoload.php');
+
+// The following includes are needed when using protobuf 3.1.0
+// and will suppress warnings when using protobuf 3.2.0+
 @include_once dirname(__FILE__).'/math.pb.php';
 @include_once dirname(__FILE__).'/math_grpc_pb.php';
 
diff --git a/src/php/tests/interop/interop_client.php b/src/php/tests/interop/interop_client.php
index e9b4e5ffabbf9ce63ac0da764f7854af1eb8025d..cf93ac39e0814f1dffe7a0966e1788c8a92dcd95 100755
--- a/src/php/tests/interop/interop_client.php
+++ b/src/php/tests/interop/interop_client.php
@@ -32,8 +32,12 @@
  *
  */
 require_once realpath(dirname(__FILE__).'/../../vendor/autoload.php');
+
+// The following includes are needed when using protobuf 3.1.0
+// and will suppress warnings when using protobuf 3.2.0+
 @include_once 'src/proto/grpc/testing/test.pb.php';
 @include_once 'src/proto/grpc/testing/test_grpc_pb.php';
+
 use Google\Auth\CredentialsLoader;
 use Google\Auth\ApplicationDefaultCredentials;
 use GuzzleHttp\ClientInterface;