diff --git a/core/src/com/unciv/logic/BackwardCompatibility.kt b/core/src/com/unciv/logic/BackwardCompatibility.kt
index 5631341293..4b22b4af31 100644
--- a/core/src/com/unciv/logic/BackwardCompatibility.kt
+++ b/core/src/com/unciv/logic/BackwardCompatibility.kt
@@ -218,4 +218,12 @@ object BackwardCompatibility {
         }
         return false
     }
+
+    @Suppress("DEPRECATION")
+    fun GameInfo.convertOldGameSpeed() {
+        if (gameParameters.gameSpeed != "" && gameParameters.gameSpeed in ruleSet.speeds.keys) {
+            gameParameters.speed = gameParameters.gameSpeed
+            gameParameters.gameSpeed = ""
+        }
+    }
 }
diff --git a/core/src/com/unciv/logic/GameInfo.kt b/core/src/com/unciv/logic/GameInfo.kt
index 959a2b30cd..a4ac3a3cde 100644
--- a/core/src/com/unciv/logic/GameInfo.kt
+++ b/core/src/com/unciv/logic/GameInfo.kt
@@ -3,6 +3,7 @@ package com.unciv.logic
 import com.unciv.Constants
 import com.unciv.UncivGame
 import com.unciv.logic.BackwardCompatibility.convertFortify
+import com.unciv.logic.BackwardCompatibility.convertOldGameSpeed
 import com.unciv.utils.debug
 import com.unciv.logic.BackwardCompatibility.guaranteeUnitPromotions
 import com.unciv.logic.BackwardCompatibility.migrateBarbarianCamps
@@ -399,6 +400,8 @@ class GameInfo {
 
         updateGreatGeneralUniques()
 
+        convertOldGameSpeed()
+
         for (baseUnit in ruleSet.units.values)
             baseUnit.ruleset = ruleSet
 
diff --git a/core/src/com/unciv/models/metadata/GameParameters.kt b/core/src/com/unciv/models/metadata/GameParameters.kt
index f523459fbf..54f2847803 100644
--- a/core/src/com/unciv/models/metadata/GameParameters.kt
+++ b/core/src/com/unciv/models/metadata/GameParameters.kt
@@ -11,6 +11,9 @@ enum class BaseRuleset(val fullName:String){
 class GameParameters { // Default values are the default new game
     var difficulty = "Prince"
     var speed = Speed.DEFAULT
+
+    @Deprecated("Since 4.1.11")
+    var gameSpeed = ""
     var players = ArrayList<Player>().apply {
         add(Player().apply { playerType = PlayerType.Human })
         for (i in 1..3) add(Player())