diff --git a/core/src/com/unciv/models/ruleset/Nation.kt b/core/src/com/unciv/models/ruleset/Nation.kt
index 01c934a49f..472d4221df 100644
--- a/core/src/com/unciv/models/ruleset/Nation.kt
+++ b/core/src/com/unciv/models/ruleset/Nation.kt
@@ -256,7 +256,7 @@ class Nation : RulesetObject() {
                             unique.text.tr(), indent = 1)
                 }
                 for (promotion in unit.promotions.filter { it !in originalUnit.promotions }) {
-                    val effect = ruleset.unitPromotions[promotion]!!.uniquesWithEffect()
+                    val effect = ruleset.unitPromotions[promotion]!!.uniques
                     // "{$promotion} ({$effect})" won't work as effect may contain [] and tr() does not support that kind of nesting
                     textList += FormattedLine(
                         "${promotion.tr()} (${effect.joinToString(",") { it.tr() }})",
diff --git a/core/src/com/unciv/models/ruleset/Ruleset.kt b/core/src/com/unciv/models/ruleset/Ruleset.kt
index f0bf4b4e48..85cb254d09 100644
--- a/core/src/com/unciv/models/ruleset/Ruleset.kt
+++ b/core/src/com/unciv/models/ruleset/Ruleset.kt
@@ -409,12 +409,6 @@ class Ruleset {
         }
 
         for (promotion in unitPromotions.values) {
-            if (promotion.effect != "")
-                lines.add(
-                    "`Promotion.effect` used in ${promotion.name} is deprecated, please use `uniques` instead",
-                    RulesetErrorSeverity.WarningOptionsOnly
-                )
-
             checkUniques(promotion, lines, UniqueType.UniqueComplianceErrorSeverity.RulesetInvariant)
         }
 
diff --git a/core/src/com/unciv/models/ruleset/unit/Promotion.kt b/core/src/com/unciv/models/ruleset/unit/Promotion.kt
index ff025ec3a1..45fbe3579d 100644
--- a/core/src/com/unciv/models/ruleset/unit/Promotion.kt
+++ b/core/src/com/unciv/models/ruleset/unit/Promotion.kt
@@ -12,16 +12,8 @@ import com.unciv.ui.civilopedia.FormattedLine
 class Promotion : RulesetObject() {
     var prerequisites = listOf<String>()
 
-    @Deprecated("As of 3.16.12", ReplaceWith("uniques"))
-        var effect = ""
-
     var unitTypes = listOf<String>() // The json parser wouldn't agree to deserialize this as a list of UnitTypes. =(
 
-    fun uniquesWithEffect() = sequence {
-        if (effect.isNotEmpty()) yield(effect)
-        yieldAll(uniques)
-    }
-
     override fun getUniqueTarget() = UniqueTarget.Promotion
 
 
@@ -29,7 +21,7 @@ class Promotion : RulesetObject() {
     fun getDescription(promotionsForUnitType: Collection<Promotion>):String {
         val textList = ArrayList<String>()
 
-        for (unique in uniquesWithEffect()) {
+        for (unique in uniques) {
             textList += unique.tr()
         }