diff --git a/composer.json b/composer.json
index b9d49a777..5b15af71a 100644
--- a/composer.json
+++ b/composer.json
@@ -11,7 +11,7 @@
         "google/grpc-gcp": "^0.2||^0.3",
         "grpc/grpc": "^1.13",
         "google/protobuf": "^3.21.4",
-        "guzzlehttp/promises": "^1.3",
+        "guzzlehttp/promises": "^1.4||^2.0",
         "guzzlehttp/psr7": "^2.0",
         "google/common-protos": "^3.0||^4.0",
         "google/longrunning": "^0.2"
diff --git a/tests/Tests/Unit/Transport/GrpcFallbackTransportTest.php b/tests/Tests/Unit/Transport/GrpcFallbackTransportTest.php
index ee166b681..94cf41e40 100644
--- a/tests/Tests/Unit/Transport/GrpcFallbackTransportTest.php
+++ b/tests/Tests/Unit/Transport/GrpcFallbackTransportTest.php
@@ -43,7 +43,7 @@
 use Google\Rpc\Code;
 use Google\Rpc\Status;
 use GuzzleHttp\Exception\RequestException;
-use GuzzleHttp\Promise;
+use GuzzleHttp\Promise\Create;
 use GuzzleHttp\Psr7\Request;
 use GuzzleHttp\Psr7\Response;
 use Psr\Http\Message\RequestInterface;
@@ -94,7 +94,7 @@ public function testStartUnaryCall($apiEndpoint, $requestMessage)
         $httpHandler = function (RequestInterface $request, array $options = []) use ($expectedResponse, $expectedRequest) {
             $this->assertEquals($expectedRequest, $request);
 
-            return Promise\promise_for(
+            return Create::promiseFor(
                 new Response(
                     200,
                     [],
@@ -130,7 +130,7 @@ public function startUnaryCallDataProvider()
     public function testStartUnaryCallThrowsException()
     {
         $httpHandler = function (RequestInterface $request, array $options = []) {
-            return Promise\rejection_for(new Exception());
+            return Create::rejectionFor(new Exception());
         };
 
         $this->expectException(Exception::class);
@@ -146,7 +146,7 @@ public function testStartUnaryCallThrowsRequestException()
             $status = new Status();
             $status->setCode(Code::NOT_FOUND);
             $status->setMessage("Ruh-roh");
-            return Promise\rejection_for(
+            return Create::rejectionFor(
                 RequestException::create(
                     new Request('POST', 'http://www.example.com'),
                     new Response(
@@ -219,7 +219,7 @@ public function buildInvalidData()
     public function testNonBinaryProtobufResponseException()
     {
         $httpHandler = function (RequestInterface $request, array $options = []) {
-            return Promise\rejection_for(
+            return Create::rejectionFor(
                 RequestException::create(
                     new Request('POST', 'http://www.example.com'),
                     new Response(