diff --git a/trackings.go b/trackings.go
index 2a7ea84..dba1ff3 100644
--- a/trackings.go
+++ b/trackings.go
@@ -13,7 +13,7 @@ import (
 // CreateTrackingParams provides parameters for new Tracking API request
 type CreateTrackingParams struct {
 	TrackingNumber             string            `json:"tracking_number"`                        // Tracking number of a shipment.
-	Slug                       []string          `json:"slug,omitempty"`                         // Unique code of each courier. If you do not specify a slug, AfterShip will automatically detect the courier based on the tracking number format and your selected couriers.
+	Slug                       string            `json:"slug,omitempty"`                         // Unique code of each courier. If you do not specify a slug, AfterShip will automatically detect the courier based on the tracking number format and your selected couriers.
 	TrackingPostalCode         string            `json:"tracking_postal_code,omitempty"`         // The postal code of receiver's address. Required by some couriers, such as deutsch-post
 	TrackingShipDate           string            `json:"tracking_ship_date,omitempty"`           // Shipping date in YYYYMMDD format. Required by some couriers, such as deutsch-post
 	TrackingAccountNumber      string            `json:"tracking_account_number,omitempty"`      // Account number of the shipper for a specific courier. Required by some couriers, such as dynamic-logistics
diff --git a/trackings_example_test.go b/trackings_example_test.go
index 22d836e..ec6df3e 100644
--- a/trackings_example_test.go
+++ b/trackings_example_test.go
@@ -23,7 +23,7 @@ func ExampleClient_CreateTracking() {
 	trackingNumber := strconv.FormatInt(time.Now().Unix(), 10)
 	newTracking := aftership.CreateTrackingParams{
 		TrackingNumber: trackingNumber,
-		Slug:           []string{"dhl"},
+		Slug:           "dhl",
 		Title:          "Title Name",
 		SMSes: []string{
 			"+18555072509",
diff --git a/trackings_test.go b/trackings_test.go
index 8a45aa8..f652110 100644
--- a/trackings_test.go
+++ b/trackings_test.go
@@ -83,7 +83,7 @@ func TestCreateTracking(t *testing.T) {
 	})
 
 	params := CreateTrackingParams{
-		Slug:           []string{"dhl"},
+		Slug:           "dhl",
 		TrackingNumber: "123456789",
 		Title:          "Title Name",
 		SMSes: []string{
diff --git a/version.go b/version.go
index 23295e6..a086af4 100644
--- a/version.go
+++ b/version.go
@@ -1,4 +1,4 @@
 package aftership
 
 // VERSION is the version number of this package
-const VERSION string = "2.0.0"
+const VERSION string = "2.0.2"