diff --git a/src/go/cmd/mock_server/mock_server.go b/src/go/cmd/mock_server/mock_server.go
index 81cc917a83a5..c6aabe1c33ad 100644
--- a/src/go/cmd/mock_server/mock_server.go
+++ b/src/go/cmd/mock_server/mock_server.go
@@ -58,7 +58,7 @@ func handleConnection(c *zbxcomms.Connection) {
 
 	switch pairs["request"] {
 	case "active checks":
-		activeChecks, err := ioutil.ReadFile(options.ActiveChecksFile)
+		activeChecks, err := os.ReadFile(options.ActiveChecksFile)
 		if err == nil {
 			err = c.Write(activeChecks)
 		}