diff --git a/command.go b/command.go
index 6e09a32..0a6b6ed 100644
--- a/command.go
+++ b/command.go
@@ -253,7 +253,7 @@ func reorderArgs(commandFlags []Flag, args []string) []string {
 
 func argIsFlag(commandFlags []Flag, arg string) bool {
 	// this line turns `--flag` into `flag`
-	arg = strings.ReplaceAll(arg, "-", "")
+	arg = strings.Replace(arg, "-", "", -1)
 	// this line turns `flag=value` into `flag`
 	arg = strings.Split(arg, "=")[0]
 	// look through all the flags, to see if the `arg` is one of our flags