diff --git a/OpenRA.Mods.RA/Missions/Allies01Script.cs b/OpenRA.Mods.RA/Missions/Allies01Script.cs
index ca4eae1245..65c6ea8bf0 100644
--- a/OpenRA.Mods.RA/Missions/Allies01Script.cs
+++ b/OpenRA.Mods.RA/Missions/Allies01Script.cs
@@ -8,14 +8,15 @@
  */
 #endregion
 
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using OpenRA.FileFormats;
+using OpenRA.Mods.RA.Activities;
 using OpenRA.Mods.RA.Air;
 using OpenRA.Mods.RA.Move;
 using OpenRA.Scripting;
 using OpenRA.Traits;
-using OpenRA.Mods.RA.Activities;
 
 namespace OpenRA.Mods.RA.Missions
 {
@@ -23,7 +24,7 @@ namespace OpenRA.Mods.RA.Missions
 
 	class Allies01Script : IHasObjectives, IWorldLoaded, ITick
 	{
-		public event ObjectivesUpdatedEventHandler OnObjectivesUpdated = notify => { };
+		public event Action<bool> OnObjectivesUpdated = notify => { };
 
 		public IEnumerable<Objective> Objectives { get { return objectives.Values; } }
 
diff --git a/OpenRA.Mods.RA/Missions/Allies02Script.cs b/OpenRA.Mods.RA/Missions/Allies02Script.cs
index a3fc9e8433..e728df1822 100644
--- a/OpenRA.Mods.RA/Missions/Allies02Script.cs
+++ b/OpenRA.Mods.RA/Missions/Allies02Script.cs
@@ -8,6 +8,7 @@
  */
 #endregion
 
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using OpenRA.FileFormats;
@@ -25,7 +26,7 @@ namespace OpenRA.Mods.RA.Missions
 
 	class Allies02Script : IHasObjectives, IWorldLoaded, ITick
 	{
-		public event ObjectivesUpdatedEventHandler OnObjectivesUpdated = notify => { };
+		public event Action<bool> OnObjectivesUpdated = notify => { };
 
 		public IEnumerable<Objective> Objectives { get { return objectives.Values; } }
 
diff --git a/OpenRA.Mods.RA/Missions/Allies03Script.cs b/OpenRA.Mods.RA/Missions/Allies03Script.cs
index f412948be0..649e97def6 100644
--- a/OpenRA.Mods.RA/Missions/Allies03Script.cs
+++ b/OpenRA.Mods.RA/Missions/Allies03Script.cs
@@ -26,7 +26,7 @@ namespace OpenRA.Mods.RA.Missions
 
 	class Allies03Script : IHasObjectives, IWorldLoaded, ITick
 	{
-		public event ObjectivesUpdatedEventHandler OnObjectivesUpdated = notify => { };
+		public event Action<bool> OnObjectivesUpdated = notify => { };
 
 		public IEnumerable<Objective> Objectives { get { return objectives.Values; } }
 
diff --git a/OpenRA.Mods.RA/Missions/Allies04Script.cs b/OpenRA.Mods.RA/Missions/Allies04Script.cs
index 646919fda1..f285d94936 100644
--- a/OpenRA.Mods.RA/Missions/Allies04Script.cs
+++ b/OpenRA.Mods.RA/Missions/Allies04Script.cs
@@ -25,7 +25,7 @@ namespace OpenRA.Mods.RA.Missions
 
 	class Allies04Script : IHasObjectives, IWorldLoaded, ITick
 	{
-		public event ObjectivesUpdatedEventHandler OnObjectivesUpdated = notify => { };
+		public event Action<bool> OnObjectivesUpdated = notify => { };
 
 		public IEnumerable<Objective> Objectives { get { return objectives.Values; } }
 
diff --git a/OpenRA.Mods.RA/Missions/Objective.cs b/OpenRA.Mods.RA/Missions/Objective.cs
index 263858b571..b0142c2205 100644
--- a/OpenRA.Mods.RA/Missions/Objective.cs
+++ b/OpenRA.Mods.RA/Missions/Objective.cs
@@ -8,6 +8,7 @@
  */
 #endregion
 
+using System;
 using System.Collections.Generic;
 using OpenRA.Traits;
 
@@ -30,11 +31,9 @@ namespace OpenRA.Mods.RA.Missions
 	public enum ObjectiveType { Primary, Secondary }
 	public enum ObjectiveStatus { Inactive, InProgress, Completed, Failed }
 
-	public delegate void ObjectivesUpdatedEventHandler(bool notify);
-
 	public interface IHasObjectives
 	{
-		event ObjectivesUpdatedEventHandler OnObjectivesUpdated;
+		event Action<bool> OnObjectivesUpdated;
 		IEnumerable<Objective> Objectives { get; }
 	}
 
diff --git a/OpenRA.Mods.RA/Missions/Soviet01ClassicScript.cs b/OpenRA.Mods.RA/Missions/Soviet01ClassicScript.cs
index f3cf682048..8ab3192de2 100644
--- a/OpenRA.Mods.RA/Missions/Soviet01ClassicScript.cs
+++ b/OpenRA.Mods.RA/Missions/Soviet01ClassicScript.cs
@@ -8,6 +8,7 @@
  */
 #endregion
 
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using OpenRA.FileFormats;
@@ -24,7 +25,7 @@ namespace OpenRA.Mods.RA.Missions
 
 	class Soviet01ClassicScript : IHasObjectives, IWorldLoaded, ITick
 	{
-		public event ObjectivesUpdatedEventHandler OnObjectivesUpdated = notify => { };
+		public event Action<bool> OnObjectivesUpdated = notify => { };
 
 		public IEnumerable<Objective> Objectives { get { return objectives.Values; } }