diff --git a/lib/src/options.dart b/lib/src/options.dart
index c80370b..1b2aee0 100644
--- a/lib/src/options.dart
+++ b/lib/src/options.dart
@@ -110,8 +110,8 @@
     }
   }
 
-  static showUsage(parser) {
+  static showUsage(ArgParser parser) {
     print('Usage: css [options...] input.css');
-    print(parser.getUsage());
+    print(parser.usage);
   }
 }
diff --git a/pubspec.yaml b/pubspec.yaml
index d8c2029..5bf4142 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -6,7 +6,7 @@
 environment:
   sdk: '>=1.21.0 <2.0.0'
 dependencies:
-  args: '>=0.9.0 <0.14.0'
+  args: '>=0.12.1 <2.0.0'
   logging: '>=0.9.0 <0.12.0'
   path: '>=0.9.0 <2.0.0'
   source_span: '>=1.4.0 <2.0.0'