diff --git a/src/main/kotlin/com/ecwid/apiclient/v3/converter/FetchedOrder.kt b/src/main/kotlin/com/ecwid/apiclient/v3/converter/FetchedOrder.kt
index 76af5e35..117b83c6 100644
--- a/src/main/kotlin/com/ecwid/apiclient/v3/converter/FetchedOrder.kt
+++ b/src/main/kotlin/com/ecwid/apiclient/v3/converter/FetchedOrder.kt
@@ -93,6 +93,7 @@ fun FetchedOrder.toUpdated(): UpdatedOrder {
 		paymentReference = paymentReference,
 		loyalty = loyalty?.toUpdated(),
 		customerFiscalCode = customerFiscalCode,
+		lang = lang,
 	)
 }
 
diff --git a/src/main/kotlin/com/ecwid/apiclient/v3/dto/order/request/UpdatedOrder.kt b/src/main/kotlin/com/ecwid/apiclient/v3/dto/order/request/UpdatedOrder.kt
index cdca867a..f2ad6c9c 100644
--- a/src/main/kotlin/com/ecwid/apiclient/v3/dto/order/request/UpdatedOrder.kt
+++ b/src/main/kotlin/com/ecwid/apiclient/v3/dto/order/request/UpdatedOrder.kt
@@ -97,6 +97,7 @@ data class UpdatedOrder(
 	val paymentReference: String? = null,
 	val loyalty: Loyalty? = null,
 	val customerFiscalCode: String? = null,
+	val lang: String? = null,
 
 ) : ApiUpdatedDTO {
 
diff --git a/src/main/kotlin/com/ecwid/apiclient/v3/dto/order/result/FetchedOrder.kt b/src/main/kotlin/com/ecwid/apiclient/v3/dto/order/result/FetchedOrder.kt
index db85e017..d6daea41 100644
--- a/src/main/kotlin/com/ecwid/apiclient/v3/dto/order/result/FetchedOrder.kt
+++ b/src/main/kotlin/com/ecwid/apiclient/v3/dto/order/result/FetchedOrder.kt
@@ -119,6 +119,7 @@ data class FetchedOrder(
 	val shippingLabelAvailableForShipment: Boolean = false,
 	val loyalty: Loyalty? = null,
 	val customerFiscalCode: String? = null,
+	val lang: String? = null,
 
 	) : ApiFetchedDTO, ApiResultDTO {
 
diff --git a/src/test/kotlin/com/ecwid/apiclient/v3/entity/CartsTest.kt b/src/test/kotlin/com/ecwid/apiclient/v3/entity/CartsTest.kt
index 71f89015..eba8613d 100644
--- a/src/test/kotlin/com/ecwid/apiclient/v3/entity/CartsTest.kt
+++ b/src/test/kotlin/com/ecwid/apiclient/v3/entity/CartsTest.kt
@@ -3,6 +3,7 @@ package com.ecwid.apiclient.v3.entity
 import com.ecwid.apiclient.v3.converter.toUpdated
 import com.ecwid.apiclient.v3.dto.cart.request.*
 import com.ecwid.apiclient.v3.dto.cart.result.CalculateOrderDetailsResult
+import com.ecwid.apiclient.v3.dto.cart.result.CalculateOrderDetailsResult.DiscountInfo
 import com.ecwid.apiclient.v3.dto.order.enums.*
 import com.ecwid.apiclient.v3.dto.order.request.OrderCreateRequest
 import com.ecwid.apiclient.v3.dto.order.request.OrderDetailsRequest
@@ -352,7 +353,7 @@ class CartsTest : BaseEntityTest() {
 		checkPersonsEquals(orderForCalculate.billingPerson, calculatedOrder.billingPerson)
 		checkPersonsEquals(orderForCalculate.shippingPerson, calculatedOrder.shippingPerson)
 		assertEquals(
-			null,
+			emptyList<DiscountInfo>(),
 			calculatedOrder.discountInfo
 		) // TODO Discover why after each calculation this field resets to null
 	}
@@ -709,6 +710,7 @@ private fun UpdatedOrder.cleanupForComparison(order: UpdatedOrder): UpdatedOrder
 			it.copy(
 				appliesToItems = null
 			)
-		}
+		},
+		lang = order.lang
 	)
 }
diff --git a/src/test/kotlin/com/ecwid/apiclient/v3/entity/OrdersTest.kt b/src/test/kotlin/com/ecwid/apiclient/v3/entity/OrdersTest.kt
index 34a52968..3264cfe3 100644
--- a/src/test/kotlin/com/ecwid/apiclient/v3/entity/OrdersTest.kt
+++ b/src/test/kotlin/com/ecwid/apiclient/v3/entity/OrdersTest.kt
@@ -437,7 +437,8 @@ private fun UpdatedOrder.cleanupForComparison(order: UpdatedOrder): UpdatedOrder
 			it.copy(
 				appliesToItems = null
 			)
-		}
+		},
+		lang = order.lang
 	)
 }
 
diff --git a/src/test/kotlin/com/ecwid/apiclient/v3/rule/nullablepropertyrules/FetchedOrderRules.kt b/src/test/kotlin/com/ecwid/apiclient/v3/rule/nullablepropertyrules/FetchedOrderRules.kt
index b50d999c..9c37b0c7 100644
--- a/src/test/kotlin/com/ecwid/apiclient/v3/rule/nullablepropertyrules/FetchedOrderRules.kt
+++ b/src/test/kotlin/com/ecwid/apiclient/v3/rule/nullablepropertyrules/FetchedOrderRules.kt
@@ -321,4 +321,5 @@ val fetchedOrderNullablePropertyRules: List<NullablePropertyRule<*, *>> = listOf
 	AllowNullable(FetchedOrder.LoyaltyRedemption::amount),
 	AllowNullable(FetchedOrder.LoyaltyRedemption::cancelled),
 	AllowNullable(FetchedOrder::customerFiscalCode),
+	AllowNullable(FetchedOrder::lang),
 )
diff --git a/src/test/kotlin/com/ecwid/apiclient/v3/util/OrderUtils.kt b/src/test/kotlin/com/ecwid/apiclient/v3/util/OrderUtils.kt
index f1ba2b1d..7942d0c6 100644
--- a/src/test/kotlin/com/ecwid/apiclient/v3/util/OrderUtils.kt
+++ b/src/test/kotlin/com/ecwid/apiclient/v3/util/OrderUtils.kt
@@ -137,6 +137,7 @@ fun generateTestOrder(): UpdatedOrder {
 			),
 			refererChannel = "Referer channel " + randomAlphanumeric(8),
 		),
+		lang = "en",
 		orderExtraFields = listOf(
 			UpdatedOrder.OrderExtraFields(
 				customerInputType = "TEXT",