Updating MSAL to send client info = 2 on client credential flow

src/client/Microsoft.Identity.Client/Internal/Requests/ClientCredentialRequest.cs

@@ -335,7 +335,8 @@ private Dictionary<string, string> GetBodyParameters()
             var dict = new Dictionary<string, string>
             {
                 [OAuth2Parameter.GrantType] = OAuth2GrantType.ClientCredentials,
-                [OAuth2Parameter.Scope] = AuthenticationRequestParameters.Scope.AsSingleString()
+                [OAuth2Parameter.Scope] = AuthenticationRequestParameters.Scope.AsSingleString(),
+                [OAuth2Parameter.ClientInfo] = "2"
             };
 
             return dict;

tests/Microsoft.Identity.Test.Unit/PublicApiTests/ClientCredentialWithCertTest.cs

@@ -23,6 +23,7 @@
 using static Microsoft.Identity.Client.Internal.JsonWebToken;
 using Microsoft.Identity.Client.RP;
 using Microsoft.Identity.Client.Http;
+using Microsoft.Identity.Client.OAuth2;
 
 namespace Microsoft.Identity.Test.Unit
 {
@@ -1019,6 +1020,43 @@ public void EnsureNullCertDoesNotSetSerialNumberTestAsync()
             }
         }
 
+        [TestMethod]
+        public async Task AcquireTokenForClient_ShouldSendClientInfoParameter_WithValueTwo_Async()
+        {
+            // Arrange
+            using (var httpManager = new MockHttpManager())
+            {
+                httpManager.AddInstanceDiscoveryMockHandler();
+
+                // Set up the expected POST data to include client_info = "2"
+                var expectedPostData = new Dictionary<string, string>
+                {
+                    [OAuth2Parameter.GrantType] = OAuth2GrantType.ClientCredentials,
+                    [OAuth2Parameter.Scope] = TestConstants.s_scope.AsSingleString(),
+                    [OAuth2Parameter.ClientInfo] = "2"
+                };
+
+                var handler = httpManager.AddMockHandlerSuccessfulClientCredentialTokenResponseMessage(
+                    expectedPostData: expectedPostData);
+
+                var app = ConfidentialClientApplicationBuilder
+                    .Create(TestConstants.ClientId)
+                    .WithClientSecret(TestConstants.ClientSecret)
+                    .WithAuthority(TestConstants.AuthorityCommonTenant)
+                    .WithHttpManager(httpManager)
+                    .BuildConcrete();
+
+                // Act
+                var result = await app.AcquireTokenForClient(TestConstants.s_scope)
+                    .ExecuteAsync()
+                    .ConfigureAwait(false);
+
+                // Assert
+                Assert.IsNotNull(result);
+                Assert.AreEqual(TokenSource.IdentityProvider, result.AuthenticationResultMetadata.TokenSource);
+            }
+        }
+
         private void BeforeCacheAccess(TokenCacheNotificationArgs args)
         {
             args.TokenCache.DeserializeMsalV3(_serializedCache);