diff --git a/CHANGELOG.md b/CHANGELOG.md
index e44ac1c..581b850 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.6.4
+
+* Make compatible with the null-safe version of `args`. 
+
 ## 0.6.3
 
 * Broaden version ranges for `fixnum` and `protobuf` dependencies to make
diff --git a/bin/src/usage_exception.dart b/bin/src/usage_exception.dart
index 0f59e5f..4499da3 100644
--- a/bin/src/usage_exception.dart
+++ b/bin/src/usage_exception.dart
@@ -6,7 +6,9 @@
 import 'package:args/command_runner.dart';
 
 abstract class PrintUsageException implements Command<void> {
-  void usageException(String message) {
+  // TODO(rnystrom): Use "Never" for the return type when this package is
+  // migrated to null safety.
+  usageException(String message) {
     print(message);
     printUsage();
     exit(1);