diff --git a/src/Umbraco.Core/Models/IServerRegistration.cs b/src/Umbraco.Core/Models/IServerRegistration.cs
index 58b8e46249..8053ea0a6e 100644
--- a/src/Umbraco.Core/Models/IServerRegistration.cs
+++ b/src/Umbraco.Core/Models/IServerRegistration.cs
@@ -18,12 +18,10 @@ namespace Umbraco.Core.Models
         /// </summary>
         bool IsActive { get; set; }
 
-        // note: cannot add this because of backward compatibility
-        //
-        ///// <summary>
-        ///// Gets or sets a value indicating whether the server is master.
-        ///// </summary>
-        //bool IsMaster { get; set; }
+        /// <summary>
+        /// Gets or sets a value indicating whether the server is master.
+        /// </summary>
+        bool IsMaster { get; set; }
 
         /// <summary>
         /// Gets the date and time the registration was created.
diff --git a/src/Umbraco.Core/Services/IServerRegistrationService.cs b/src/Umbraco.Core/Services/IServerRegistrationService.cs
index d581b86f15..cc40e09ceb 100644
--- a/src/Umbraco.Core/Services/IServerRegistrationService.cs
+++ b/src/Umbraco.Core/Services/IServerRegistrationService.cs
@@ -33,19 +33,15 @@ namespace Umbraco.Core.Services
         /// <returns>All active servers.</returns>
         IEnumerable<IServerRegistration> GetActiveServers();
 
-        // note: cannot add this because of backward compatibility
-        //
-        ///// <summary>
-        ///// Gets the current server identity.
-        ///// </summary>
-        //string CurrentServerIdentity { get; }
+        /// <summary>
+        /// Gets the current server identity.
+        /// </summary>
+        string CurrentServerIdentity { get; }
 
-        // note: cannot add this because of backward compatibility
-        //
-        ///// <summary>
-        ///// Gets the role of the current server.
-        ///// </summary>
-        ///// <returns>The role of the current server.</returns>
-        //ServerRole GetCurrentServerRole();
+        /// <summary>
+        /// Gets the role of the current server.
+        /// </summary>
+        /// <returns>The role of the current server.</returns>
+        ServerRole GetCurrentServerRole();
     }
 }
\ No newline at end of file
diff --git a/src/Umbraco.Core/Services/ServerRegistrationService.cs b/src/Umbraco.Core/Services/ServerRegistrationService.cs
index 81e6a39add..43329ebe5f 100644
--- a/src/Umbraco.Core/Services/ServerRegistrationService.cs
+++ b/src/Umbraco.Core/Services/ServerRegistrationService.cs
@@ -53,8 +53,7 @@ namespace Umbraco.Core.Services
             {
                 var regs = xr.Repository.GetAll().ToArray(); // faster to query only once
                 var hasMaster = regs.Any(x => ((ServerRegistration)x).IsMaster);
-                var iserver = regs.FirstOrDefault(x => x.ServerIdentity.InvariantEquals(serverIdentity));
-                var server = iserver as ServerRegistration; // because IServerRegistration is missing IsMaster
+                var server = regs.FirstOrDefault(x => x.ServerIdentity.InvariantEquals(serverIdentity));
                 var hasServer = server != null;
 
                 if (server == null)
@@ -96,8 +95,7 @@ namespace Umbraco.Core.Services
             _lrepo.WithWriteLocked(xr =>
             {
                 var query = Query<IServerRegistration>.Builder.Where(x => x.ServerIdentity.ToUpper() == serverIdentity.ToUpper());
-                var iserver = xr.Repository.GetByQuery(query).FirstOrDefault();
-                var server = iserver as ServerRegistration; // because IServerRegistration is missing IsMaster
+                var server = xr.Repository.GetByQuery(query).FirstOrDefault();
                 if (server == null) return;
 
                 server.IsActive = false;
diff --git a/src/Umbraco.Core/Sync/DatabaseServerRegistrar.cs b/src/Umbraco.Core/Sync/DatabaseServerRegistrar.cs
index 8ac40c1a51..666e2105db 100644
--- a/src/Umbraco.Core/Sync/DatabaseServerRegistrar.cs
+++ b/src/Umbraco.Core/Sync/DatabaseServerRegistrar.cs
@@ -43,7 +43,7 @@ namespace Umbraco.Core.Sync
         /// </summary>
         public ServerRole GetCurrentServerRole()
         {
-            var service = _registrationService.Value as ServerRegistrationService;
+            var service = _registrationService.Value;
             return service.GetCurrentServerRole();
         }
 
diff --git a/src/Umbraco.Tests/ApplicationUrlHelperTests.cs b/src/Umbraco.Tests/ApplicationUrlHelperTests.cs
index 340467d07c..578a569104 100644
--- a/src/Umbraco.Tests/ApplicationUrlHelperTests.cs
+++ b/src/Umbraco.Tests/ApplicationUrlHelperTests.cs
@@ -57,6 +57,8 @@ namespace Umbraco.Tests
                 && section.WebRouting == Mock.Of<IWebRoutingSection>(wrSection => wrSection.UmbracoApplicationUrl == (string)null)
                 && section.ScheduledTasks == Mock.Of<IScheduledTasksSection>());
 
+            ApplicationUrlHelper.ApplicationUrlProvider = request => "http://server1.com/umbraco";
+
             Initialize(settings);
 
             var appCtx = new ApplicationContext(CacheHelper.CreateDisabledCacheHelper(),
@@ -64,7 +66,6 @@ namespace Umbraco.Tests
 
             ConfigurationManager.AppSettings.Set("umbracoUseSSL", "true"); // does not make a diff here
 
-            ApplicationUrlHelper.ApplicationUrlProvider = request => "http://server1.com/umbraco";
             ApplicationUrlHelper.EnsureApplicationUrl(appCtx, settings: settings);
 
             Assert.AreEqual("http://server1.com/umbraco", appCtx._umbracoApplicationUrl);
diff --git a/src/Umbraco.Web/Strategies/ServerRegistrationEventHandler.cs b/src/Umbraco.Web/Strategies/ServerRegistrationEventHandler.cs
index b23c0870bc..2a61d4177d 100644
--- a/src/Umbraco.Web/Strategies/ServerRegistrationEventHandler.cs
+++ b/src/Umbraco.Web/Strategies/ServerRegistrationEventHandler.cs
@@ -75,7 +75,7 @@ namespace Umbraco.Web.Strategies
                 _lastUpdated = DateTime.Now;
             }
 
-            var svc = e.UmbracoContext.Application.Services.ServerRegistrationService as ServerRegistrationService;
+            var svc = e.UmbracoContext.Application.Services.ServerRegistrationService;
 
             // because
             // - ApplicationContext.UmbracoApplicationUrl is initialized by UmbracoModule in BeginRequest
diff --git a/src/Umbraco.Web/UI/LegacyDialogHandler.cs b/src/Umbraco.Web/UI/LegacyDialogHandler.cs
index 5ae7d0c627..dfa7fbc153 100644
--- a/src/Umbraco.Web/UI/LegacyDialogHandler.cs
+++ b/src/Umbraco.Web/UI/LegacyDialogHandler.cs
@@ -193,10 +193,18 @@ namespace Umbraco.Web.UI
             typeInstance.Alias = text;
 
             // check for returning url
-            var returnUrlTask = typeInstance as LegacyDialogTask;
-
-            returnUrlTask.AdditionalValues = additionalValues;
-
+            ITaskReturnUrl returnUrlTask = typeInstance as LegacyDialogTask;
+            if (returnUrlTask != null)
+            {
+                // if castable to LegacyDialogTask: add in additionalValues
+                ((LegacyDialogTask) returnUrlTask).AdditionalValues = additionalValues;
+            }
+            else
+            {
+                // otherwise cast to returnUrl interface
+                returnUrlTask = typeInstance as ITaskReturnUrl;
+            }
+            
             typeInstance.Save();
             
             return returnUrlTask != null