diff --git a/Apps/FailoverApp/Address.cs b/Apps/FailoverApp/Address.cs
index 9057a5ba..5266b524 100644
--- a/Apps/FailoverApp/Address.cs
+++ b/Apps/FailoverApp/Address.cs
@@ -1,6 +1,6 @@
 /*
 Technitium DNS Server
-Copyright (C) 2023  Shreyas Zare (shreyas@technitium.com)
+Copyright (C) 2024  Shreyas Zare (shreyas@technitium.com)
 
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
@@ -37,7 +37,7 @@ namespace Failover
         Secondary = 2
     }
 
-    public class Address : IDnsApplication, IDnsAppRecordRequestHandler
+    public sealed class Address : IDnsApplication, IDnsAppRecordRequestHandler
     {
         #region variables
 
diff --git a/Apps/FailoverApp/CNAME.cs b/Apps/FailoverApp/CNAME.cs
index e6fc8141..fb1e7513 100644
--- a/Apps/FailoverApp/CNAME.cs
+++ b/Apps/FailoverApp/CNAME.cs
@@ -1,6 +1,6 @@
 /*
 Technitium DNS Server
-Copyright (C) 2023  Shreyas Zare (shreyas@technitium.com)
+Copyright (C) 2024  Shreyas Zare (shreyas@technitium.com)
 
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
@@ -29,7 +29,7 @@ using TechnitiumLibrary.Net.Dns.ResourceRecords;
 
 namespace Failover
 {
-    public class CNAME : IDnsApplication, IDnsAppRecordRequestHandler
+    public sealed class CNAME : IDnsApplication, IDnsAppRecordRequestHandler
     {
         #region variables
 
@@ -56,7 +56,7 @@ namespace Failover
 
         #region private
 
-        private IReadOnlyList<DnsResourceRecord> GetAnswers(string domain, DnsQuestionRecord question, string zoneName, uint appRecordTtl, string healthCheck, Uri healthCheckUrl)
+        private DnsResourceRecord[] GetAnswers(string domain, DnsQuestionRecord question, string zoneName, uint appRecordTtl, string healthCheck, Uri healthCheckUrl)
         {
             HealthCheckResponse response = _healthService.QueryStatus(domain, question.Type, healthCheck, healthCheckUrl, true);
             switch (response.Status)
diff --git a/Apps/FailoverApp/EmailAlert.cs b/Apps/FailoverApp/EmailAlert.cs
index d45c8d56..fe0fa350 100644
--- a/Apps/FailoverApp/EmailAlert.cs
+++ b/Apps/FailoverApp/EmailAlert.cs
@@ -1,6 +1,6 @@
 /*
 Technitium DNS Server
-Copyright (C) 2022  Shreyas Zare (shreyas@technitium.com)
+Copyright (C) 2024  Shreyas Zare (shreyas@technitium.com)
 
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
@@ -19,7 +19,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 using DnsServerCore.ApplicationCommon;
 using System;
-using System.Collections.Generic;
 using System.Net;
 using System.Net.Mail;
 using System.Text;
@@ -348,7 +347,7 @@ DNS Failover App
         public bool Enabled
         { get { return _enabled; } }
 
-        public IReadOnlyList<MailAddress> AlertTo
+        public MailAddress[] AlertTo
         { get { return _alertTo; } }
 
         public string SmtpServer
diff --git a/Apps/FailoverApp/HealthService.cs b/Apps/FailoverApp/HealthService.cs
index dcc73c30..40c741b3 100644
--- a/Apps/FailoverApp/HealthService.cs
+++ b/Apps/FailoverApp/HealthService.cs
@@ -1,6 +1,6 @@
 /*
 Technitium DNS Server
-Copyright (C) 2023  Shreyas Zare (shreyas@technitium.com)
+Copyright (C) 2024  Shreyas Zare (shreyas@technitium.com)
 
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
@@ -420,16 +420,16 @@ namespace Failover
 
         #region properties
 
-        public IReadOnlyDictionary<string, HealthCheck> HealthChecks
+        public ConcurrentDictionary<string, HealthCheck> HealthChecks
         { get { return _healthChecks; } }
 
-        public IReadOnlyDictionary<string, EmailAlert> EmailAlerts
+        public ConcurrentDictionary<string, EmailAlert> EmailAlerts
         { get { return _emailAlerts; } }
 
-        public IReadOnlyDictionary<string, WebHook> WebHooks
+        public ConcurrentDictionary<string, WebHook> WebHooks
         { get { return _webHooks; } }
 
-        public IReadOnlyDictionary<NetworkAddress, bool> UnderMaintenance
+        public ConcurrentDictionary<NetworkAddress, bool> UnderMaintenance
         { get { return _underMaintenance; } }
 
         public IDnsServer DnsServer
diff --git a/Apps/FailoverApp/WebHook.cs b/Apps/FailoverApp/WebHook.cs
index ee2b8517..f19c1933 100644
--- a/Apps/FailoverApp/WebHook.cs
+++ b/Apps/FailoverApp/WebHook.cs
@@ -1,6 +1,6 @@
 /*
 Technitium DNS Server
-Copyright (C) 2023  Shreyas Zare (shreyas@technitium.com)
+Copyright (C) 2024  Shreyas Zare (shreyas@technitium.com)
 
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
@@ -330,7 +330,7 @@ namespace Failover
         public bool Enabled
         { get { return _enabled; } }
 
-        public IReadOnlyList<Uri> Urls
+        public Uri[] Urls
         { get { return _urls; } }
 
         #endregion