diff --git a/requirements-dev.txt b/requirements-dev.txt
index b2a36741..bf3063e8 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -139,7 +139,7 @@ hpack==4.0.0 ; python_full_version >= '3.6.1'
 
 httpcore==1.0.7 ; python_version >= '3.7'
 
-httpx[http2]==0.27.2
+httpx[http2]==0.28.0
 
 hyperframe==6.0.1 ; python_full_version >= '3.6.1'
 
diff --git a/tests/test_graph_client_factory.py b/tests/test_graph_client_factory.py
index 36138555..9055b1a1 100644
--- a/tests/test_graph_client_factory.py
+++ b/tests/test_graph_client_factory.py
@@ -41,11 +41,11 @@ def test_create_with_default_middleware_custom_client():
 def test_create_with_default_middleware_custom_client_with_proxy():
     """Test creation of GraphClient using default middleware"""
     proxies = {
-        "http://": "http://localhost:8030",
-        "https://": "http://localhost:8031",
+        "http://": httpx.HTTPTransport(proxy="http://localhost:8030"),
+        "https://": httpx.HTTPTransport(proxy="http://localhost:8031"),
     }
     timeout = httpx.Timeout(20, connect=10)
-    custom_client = httpx.AsyncClient(timeout=timeout, http2=True, proxies=proxies)
+    custom_client = httpx.AsyncClient(timeout=timeout, http2=True, mounts=proxies)
     client = GraphClientFactory.create_with_default_middleware(client=custom_client)
 
     assert isinstance(client, httpx.AsyncClient)
@@ -98,11 +98,11 @@ def test_create_with_custom_middleware_custom_client():
 def test_create_with_custom_middleware_custom_client_with_proxy():
     """Test creation of HTTP Clients with custom middleware"""
     proxies = {
-        "http://": "http://localhost:8030",
-        "https://": "http://localhost:8031",
+        "http://": httpx.HTTPTransport(proxy="http://localhost:8030"),
+        "https://": httpx.HTTPTransport(proxy="http://localhost:8031"),
     }
     timeout = httpx.Timeout(20, connect=10)
-    custom_client = httpx.AsyncClient(timeout=timeout, http2=True, proxies=proxies)
+    custom_client = httpx.AsyncClient(timeout=timeout, http2=True, mounts=proxies)
     middleware = [
         GraphTelemetryHandler(),
     ]