diff --git a/src/Core/Services/IPushNotificationService.cs b/src/Core/Services/IPushNotificationService.cs
index 52b68c7846..fe26e9a843 100644
--- a/src/Core/Services/IPushNotificationService.cs
+++ b/src/Core/Services/IPushNotificationService.cs
@@ -29,9 +29,9 @@ public interface IPushNotificationService
     Task PushAuthRequestAsync(AuthRequest authRequest);
     Task PushAuthRequestResponseAsync(AuthRequest authRequest);
 
-    Task SendPayloadToUserAsync(string userId, PushType type, object payload, string identifier,
+    Task SendPayloadToUserAsync(string userId, PushType type, object payload, string? identifier,
         string? deviceId = null, ClientType? clientType = null);
 
-    Task SendPayloadToOrganizationAsync(string orgId, PushType type, object payload, string identifier,
+    Task SendPayloadToOrganizationAsync(string orgId, PushType type, object payload, string? identifier,
         string? deviceId = null, ClientType? clientType = null);
 }
diff --git a/src/Core/Services/Implementations/AzureQueuePushNotificationService.cs b/src/Core/Services/Implementations/AzureQueuePushNotificationService.cs
index 0855effe50..3dd93e5d2d 100644
--- a/src/Core/Services/Implementations/AzureQueuePushNotificationService.cs
+++ b/src/Core/Services/Implementations/AzureQueuePushNotificationService.cs
@@ -230,14 +230,14 @@ public class AzureQueuePushNotificationService : IPushNotificationService
         return currentContext?.DeviceIdentifier;
     }
 
-    public Task SendPayloadToUserAsync(string userId, PushType type, object payload, string identifier,
+    public Task SendPayloadToUserAsync(string userId, PushType type, object payload, string? identifier,
         string? deviceId = null, ClientType? clientType = null)
     {
         // Noop
         return Task.FromResult(0);
     }
 
-    public Task SendPayloadToOrganizationAsync(string orgId, PushType type, object payload, string identifier,
+    public Task SendPayloadToOrganizationAsync(string orgId, PushType type, object payload, string? identifier,
         string? deviceId = null, ClientType? clientType = null)
     {
         // Noop
diff --git a/src/Core/Services/Implementations/MultiServicePushNotificationService.cs b/src/Core/Services/Implementations/MultiServicePushNotificationService.cs
index c29ba9516c..4d266a538a 100644
--- a/src/Core/Services/Implementations/MultiServicePushNotificationService.cs
+++ b/src/Core/Services/Implementations/MultiServicePushNotificationService.cs
@@ -132,14 +132,14 @@ public class MultiServicePushNotificationService : IPushNotificationService
         return Task.FromResult(0);
     }
 
-    public Task SendPayloadToUserAsync(string userId, PushType type, object payload, string identifier,
+    public Task SendPayloadToUserAsync(string userId, PushType type, object payload, string? identifier,
         string? deviceId = null, ClientType? clientType = null)
     {
         PushToServices((s) => s.SendPayloadToUserAsync(userId, type, payload, identifier, deviceId, clientType));
         return Task.FromResult(0);
     }
 
-    public Task SendPayloadToOrganizationAsync(string orgId, PushType type, object payload, string identifier,
+    public Task SendPayloadToOrganizationAsync(string orgId, PushType type, object payload, string? identifier,
         string? deviceId = null, ClientType? clientType = null)
     {
         PushToServices((s) => s.SendPayloadToOrganizationAsync(orgId, type, payload, identifier, deviceId, clientType));
diff --git a/src/Core/Services/Implementations/NotificationsApiPushNotificationService.cs b/src/Core/Services/Implementations/NotificationsApiPushNotificationService.cs
index e10179256c..dd70a72539 100644
--- a/src/Core/Services/Implementations/NotificationsApiPushNotificationService.cs
+++ b/src/Core/Services/Implementations/NotificationsApiPushNotificationService.cs
@@ -236,14 +236,14 @@ public class NotificationsApiPushNotificationService : BaseIdentityClientService
         return currentContext?.DeviceIdentifier;
     }
 
-    public Task SendPayloadToUserAsync(string userId, PushType type, object payload, string identifier,
+    public Task SendPayloadToUserAsync(string userId, PushType type, object payload, string? identifier,
         string? deviceId = null, ClientType? clientType = null)
     {
         // Noop
         return Task.FromResult(0);
     }
 
-    public Task SendPayloadToOrganizationAsync(string orgId, PushType type, object payload, string identifier,
+    public Task SendPayloadToOrganizationAsync(string orgId, PushType type, object payload, string? identifier,
         string? deviceId = null, ClientType? clientType = null)
     {
         // Noop
diff --git a/src/Core/Services/Implementations/RelayPushNotificationService.cs b/src/Core/Services/Implementations/RelayPushNotificationService.cs
index c5a934e3bf..6c1600da48 100644
--- a/src/Core/Services/Implementations/RelayPushNotificationService.cs
+++ b/src/Core/Services/Implementations/RelayPushNotificationService.cs
@@ -287,13 +287,13 @@ public class RelayPushNotificationService : BaseIdentityClientService, IPushNoti
         }
     }
 
-    public Task SendPayloadToUserAsync(string userId, PushType type, object payload, string identifier,
+    public Task SendPayloadToUserAsync(string userId, PushType type, object payload, string? identifier,
         string? deviceId = null, ClientType? clientType = null)
     {
         throw new NotImplementedException();
     }
 
-    public Task SendPayloadToOrganizationAsync(string orgId, PushType type, object payload, string identifier,
+    public Task SendPayloadToOrganizationAsync(string orgId, PushType type, object payload, string? identifier,
         string? deviceId = null, ClientType? clientType = null)
     {
         throw new NotImplementedException();
diff --git a/src/Core/Services/NoopImplementations/NoopPushNotificationService.cs b/src/Core/Services/NoopImplementations/NoopPushNotificationService.cs
index e7ee9c38d9..548c6a159e 100644
--- a/src/Core/Services/NoopImplementations/NoopPushNotificationService.cs
+++ b/src/Core/Services/NoopImplementations/NoopPushNotificationService.cs
@@ -84,7 +84,7 @@ public class NoopPushNotificationService : IPushNotificationService
         return Task.FromResult(0);
     }
 
-    public Task SendPayloadToOrganizationAsync(string orgId, PushType type, object payload, string identifier,
+    public Task SendPayloadToOrganizationAsync(string orgId, PushType type, object payload, string? identifier,
         string? deviceId = null, ClientType? clientType = null)
     {
         return Task.FromResult(0);
@@ -100,7 +100,7 @@ public class NoopPushNotificationService : IPushNotificationService
         return Task.FromResult(0);
     }
 
-    public Task SendPayloadToUserAsync(string userId, PushType type, object payload, string identifier,
+    public Task SendPayloadToUserAsync(string userId, PushType type, object payload, string? identifier,
         string? deviceId = null, ClientType? clientType = null)
     {
         return Task.FromResult(0);