diff --git a/src/main/kotlin/com/cubetiqs/money/MoneyCurrency.kt b/src/main/kotlin/com/cubetiqs/money/MoneyCurrency.kt
index ee8bda9..1f6f8f0 100644
--- a/src/main/kotlin/com/cubetiqs/money/MoneyCurrency.kt
+++ b/src/main/kotlin/com/cubetiqs/money/MoneyCurrency.kt
@@ -14,7 +14,7 @@ open class MoneyCurrency(
     private var configs: Map<String, Any?>? = null,
 ) : Serializable, StdMoney.Currency {
     override fun getCurrency(): String {
-        return name.toUpperCase().trim()
+        return name.uppercase().trim()
     }
 
     fun getSymbol(): String? {
diff --git a/src/main/kotlin/com/cubetiqs/money/MoneyExtension.kt b/src/main/kotlin/com/cubetiqs/money/MoneyExtension.kt
index 9fc5c95..f242c4d 100644
--- a/src/main/kotlin/com/cubetiqs/money/MoneyExtension.kt
+++ b/src/main/kotlin/com/cubetiqs/money/MoneyExtension.kt
@@ -8,7 +8,7 @@ infix fun StdMoney.exchangeTo(currency: StdMoney.Currency): StdMoney {
 
 infix fun StdMoney.exchangeTo(currency: String): StdMoney = this exchangeTo object : StdMoney.Currency {
     override fun getCurrency(): String {
-        return currency.toUpperCase().trim()
+        return currency.uppercase().trim()
     }
 }
 
@@ -69,7 +69,7 @@ infix fun Number.withCurrency(currency: StdMoney.Currency): StdMoney = object :
 
 infix fun Number.withCurrency(currency: String): StdMoney = this withCurrency object : StdMoney.Currency {
     override fun getCurrency(): String {
-        return currency.toUpperCase().trim()
+        return currency.uppercase().trim()
     }
 }
 
diff --git a/src/main/kotlin/com/cubetiqs/money/MoneyObject.kt b/src/main/kotlin/com/cubetiqs/money/MoneyObject.kt
index 3044098..c6e24f7 100644
--- a/src/main/kotlin/com/cubetiqs/money/MoneyObject.kt
+++ b/src/main/kotlin/com/cubetiqs/money/MoneyObject.kt
@@ -105,7 +105,7 @@ open class MoneyObject(
                             if (temp.length == 1) {
                                 operator(temp[0])
                             } else {
-                                valueOf(temp.toUpperCase().trim())
+                                valueOf(temp.uppercase().trim())
                             }
                         }
                         is Char -> {
diff --git a/src/main/kotlin/com/cubetiqs/money/StdMoney.kt b/src/main/kotlin/com/cubetiqs/money/StdMoney.kt
index 58ae491..add58c1 100644
--- a/src/main/kotlin/com/cubetiqs/money/StdMoney.kt
+++ b/src/main/kotlin/com/cubetiqs/money/StdMoney.kt
@@ -60,7 +60,7 @@ interface StdMoney : MoneyMixin {
         fun initCurrency(currency: String?): Currency {
             return object : Currency {
                 override fun getCurrency(): String {
-                    return currency?.toUpperCase()?.trim() ?: "USD"
+                    return currency?.uppercase()?.trim() ?: "USD"
                 }
             }
         }