diff --git a/days/src/main/kotlin/Day08.kt b/days/src/main/kotlin/Day08.kt
index 415e92f..8bebd1f 100644
--- a/days/src/main/kotlin/Day08.kt
+++ b/days/src/main/kotlin/Day08.kt
@@ -48,7 +48,7 @@ class Day08(@Lines val input: Input<List<String>>) {
         }
 
         for (index in possibleMutations.toArray()) {
-            val copy = instructions.clone().also {
+            val copy = instructions.copyOf().also {
                 val modifiedOperation = if (it[index].operation == Operation.Nop) Operation.Jmp else Operation.Nop
                 it[index] = it[index].copy(operation = modifiedOperation)
             }