diff --git a/OpenRA.Mods.Common/UtilityCommands/UpgradeRules.cs b/OpenRA.Mods.Common/UtilityCommands/UpgradeRules.cs
index 97d2b4c6e3..a7f1c124c1 100644
--- a/OpenRA.Mods.Common/UtilityCommands/UpgradeRules.cs
+++ b/OpenRA.Mods.Common/UtilityCommands/UpgradeRules.cs
@@ -344,6 +344,20 @@ namespace OpenRA.Mods.Common.UtilityCommands
 					node.Value.Nodes.RemoveAll(n => n.Key == "PathfinderDebugOverlay");
 				}
 
+				// AlliedMissiles on JamsMissiles was changed from a boolean to a Stances field and renamed
+				if (engineVersion < 20160827)
+				{
+					if (node.Key == "JamsMissiles")
+					{
+						var alliedMissiles = node.Value.Nodes.FirstOrDefault(n => n.Key == "AlliedMissiles");
+						if (alliedMissiles != null)
+						{
+							alliedMissiles.Value.Value = FieldLoader.GetValue<bool>("AlliedMissiles", alliedMissiles.Value.Value) ? "Ally, Neutral, Enemy" : "Neutral, Enemy";
+							alliedMissiles.Key = "DeflectionStances";
+						}
+					}
+				}
+
 				UpgradeActorRules(modData, engineVersion, ref node.Value.Nodes, node, depth + 1);
 			}
 
diff --git a/mods/ra/rules/vehicles.yaml b/mods/ra/rules/vehicles.yaml
index 1aae1c36ba..73c0d901ca 100644
--- a/mods/ra/rules/vehicles.yaml
+++ b/mods/ra/rules/vehicles.yaml
@@ -546,7 +546,7 @@ MRJ:
 		Range: 15c0
 	JamsMissiles:
 		Range: 4c0
-		AlliedMissiles: False
+		DeflectionStances: Neutral, Enemy
 	RenderJammerCircle:
 	DetectCloaked:
 		Range: 6c0