diff --git a/app_test.go b/app_test.go
index 0612132..92fc915 100644
--- a/app_test.go
+++ b/app_test.go
@@ -45,7 +45,7 @@ func TestApp_singleBurst_Success(t *testing.T) {
 	startTime := time.Now()
 
 	count := 10
-	for i := 0; i < count; i++ {
+	for range count {
 		app.wg.Add(1)
 		app.slackQueue <- SlackPostMessageRequest{
 			Channel: "mockChannel",
@@ -89,7 +89,7 @@ func TestApp_MultiBurst_Success(t *testing.T) {
 	startTime := time.Now()
 
 	count := 20
-	for i := 0; i < count; i++ {
+	for range count {
 		app.wg.Add(1)
 		app.slackQueue <- SlackPostMessageRequest{
 			Channel: "mockChannel",
@@ -133,7 +133,7 @@ func TestApp_TestSlackRequestRate(t *testing.T) {
 	startTime := time.Now()
 
 	count := 20
-	for i := 0; i < count; i++ {
+	for range count {
 		app.wg.Add(1)
 		app.slackQueue <- SlackPostMessageRequest{
 			Channel: "mockChannel",
diff --git a/go.mod b/go.mod
index 945c817..ec8e9a2 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,6 @@
 module fortio.org/slack-proxy
 
-go 1.21
+go 1.22.4
 
 require (
 	fortio.org/assert v1.2.1