diff --git a/packages/pigeon/CHANGELOG.md b/packages/pigeon/CHANGELOG.md
index ba7a33836b..f3622b48ab 100644
--- a/packages/pigeon/CHANGELOG.md
+++ b/packages/pigeon/CHANGELOG.md
@@ -1,3 +1,9 @@
+## 0.1.4
+
+* Fixed nullability for NSError's in generated objc code.
+* Fixed nullability of nested objects in the Dart generator.
+* Added test to make sure the pigeon version is correct in generated code headers.
+
 ## 0.1.3
 
 * Added error message if supported datatypes are used as arguments or return
diff --git a/packages/pigeon/lib/dart_generator.dart b/packages/pigeon/lib/dart_generator.dart
index 989f9d3a92..baea13ecb3 100644
--- a/packages/pigeon/lib/dart_generator.dart
+++ b/packages/pigeon/lib/dart_generator.dart
@@ -151,7 +151,8 @@ void generateDart(Root root, StringSink sink) {
         for (Field field in klass.fields) {
           indent.write('pigeonMap[\'${field.name}\'] = ');
           if (customClassNames.contains(field.dataType)) {
-            indent.addln('${field.name}._toMap();');
+            indent.addln(
+                '${field.name} == null ? null : ${field.name}._toMap();');
           } else {
             indent.addln('${field.name};');
           }
@@ -162,6 +163,10 @@ void generateDart(Root root, StringSink sink) {
       indent.write(
           'static ${klass.name} _fromMap(Map<dynamic, dynamic> pigeonMap) ');
       indent.scoped('{', '}', () {
+        indent.write('if (pigeonMap == null)');
+        indent.scoped('{', '}', () {
+          indent.writeln('return null;');
+        });
         indent.writeln('final ${klass.name} result = ${klass.name}();');
         for (Field field in klass.fields) {
           indent.write('result.${field.name} = ');
diff --git a/packages/pigeon/lib/generator_tools.dart b/packages/pigeon/lib/generator_tools.dart
index c65c2f2509..db3157c7ff 100644
--- a/packages/pigeon/lib/generator_tools.dart
+++ b/packages/pigeon/lib/generator_tools.dart
@@ -8,7 +8,7 @@ import 'dart:mirrors';
 import 'ast.dart';
 
 /// The current version of pigeon.
-const String pigeonVersion = '0.1.2';
+const String pigeonVersion = '0.1.4';
 
 /// Read all the content from [stdin] to a String.
 String readStdin() {
diff --git a/packages/pigeon/lib/objc_generator.dart b/packages/pigeon/lib/objc_generator.dart
index fb52f0b9c3..e264ef35e2 100644
--- a/packages/pigeon/lib/objc_generator.dart
+++ b/packages/pigeon/lib/objc_generator.dart
@@ -28,8 +28,8 @@ String _className(String prefix, String className) {
 
 String _callbackForType(String dartType, String objcType) {
   return dartType == 'void'
-      ? 'void(^)(NSError*)'
-      : 'void(^)($objcType*, NSError*)';
+      ? 'void(^)(NSError* _Nullable)'
+      : 'void(^)($objcType*, NSError* _Nullable)';
 }
 
 const Map<String, String> _objcTypeForDartTypeMap = <String, String>{
diff --git a/packages/pigeon/mock_handler_tester/test/message.dart b/packages/pigeon/mock_handler_tester/test/message.dart
index 9f0db48b7e..1aa33c6494 100644
--- a/packages/pigeon/mock_handler_tester/test/message.dart
+++ b/packages/pigeon/mock_handler_tester/test/message.dart
@@ -17,6 +17,9 @@ class SearchReply {
 
   // ignore: unused_element
   static SearchReply _fromMap(Map<dynamic, dynamic> pigeonMap) {
+    if (pigeonMap == null) {
+      return null;
+    }
     final SearchReply result = SearchReply();
     result.result = pigeonMap['result'];
     result.error = pigeonMap['error'];
@@ -39,6 +42,9 @@ class SearchRequest {
 
   // ignore: unused_element
   static SearchRequest _fromMap(Map<dynamic, dynamic> pigeonMap) {
+    if (pigeonMap == null) {
+      return null;
+    }
     final SearchRequest result = SearchRequest();
     result.query = pigeonMap['query'];
     result.anInt = pigeonMap['anInt'];
@@ -52,12 +58,15 @@ class Nested {
   // ignore: unused_element
   Map<dynamic, dynamic> _toMap() {
     final Map<dynamic, dynamic> pigeonMap = <dynamic, dynamic>{};
-    pigeonMap['request'] = request._toMap();
+    pigeonMap['request'] = request == null ? null : request._toMap();
     return pigeonMap;
   }
 
   // ignore: unused_element
   static Nested _fromMap(Map<dynamic, dynamic> pigeonMap) {
+    if (pigeonMap == null) {
+      return null;
+    }
     final Nested result = Nested();
     result.request = SearchRequest._fromMap(pigeonMap['request']);
     return result;
@@ -105,6 +114,23 @@ class NestedApi {
   }
 }
 
+abstract class TestNestedApi {
+  SearchReply search(Nested arg);
+  static void setup(TestNestedApi api) {
+    {
+      const BasicMessageChannel<dynamic> channel = BasicMessageChannel<dynamic>(
+          'dev.flutter.pigeon.NestedApi.search', StandardMessageCodec());
+      channel.setMockMessageHandler((dynamic message) async {
+        final Map<dynamic, dynamic> mapMessage =
+            message as Map<dynamic, dynamic>;
+        final Nested input = Nested._fromMap(mapMessage);
+        final SearchReply output = api.search(input);
+        return <dynamic, dynamic>{'result': output._toMap()};
+      });
+    }
+  }
+}
+
 class Api {
   Future<SearchReply> search(SearchRequest arg) async {
     final Map<dynamic, dynamic> requestMap = arg._toMap();
diff --git a/packages/pigeon/mock_handler_tester/test/widget_test.dart b/packages/pigeon/mock_handler_tester/test/widget_test.dart
index 82f652a8ef..41322b3e9e 100644
--- a/packages/pigeon/mock_handler_tester/test/widget_test.dart
+++ b/packages/pigeon/mock_handler_tester/test/widget_test.dart
@@ -14,10 +14,32 @@ class Mock implements TestHostApi {
   }
 }
 
+class MockNested implements TestNestedApi {
+  bool didCall = false;
+  @override
+  SearchReply search(Nested arg) {
+    didCall = true;
+    if (arg.request == null) {
+      return SearchReply();
+    } else {
+      return SearchReply()..result = arg.request.query;
+    }
+  }
+}
+
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
 
-  test('description', () async {
+  test('simple', () async {
+    final NestedApi api = NestedApi();
+    final MockNested mock = MockNested();
+    TestNestedApi.setup(mock);
+    final SearchReply reply = await api.search(Nested()..request = null);
+    expect(mock.didCall, true);
+    expect(reply.result, null);
+  });
+
+  test('nested', () async {
     final Api api = Api();
     final Mock mock = Mock();
     TestHostApi.setup(mock);
diff --git a/packages/pigeon/pigeons/message.dart b/packages/pigeon/pigeons/message.dart
index 73dc13843e..2dff2f090e 100644
--- a/packages/pigeon/pigeons/message.dart
+++ b/packages/pigeon/pigeons/message.dart
@@ -27,7 +27,7 @@ class Nested {
   SearchRequest request;
 }
 
-@HostApi()
+@HostApi(dartHostTestHandler: 'TestNestedApi')
 abstract class NestedApi {
   SearchReply search(Nested nested);
 }
diff --git a/packages/pigeon/pubspec.yaml b/packages/pigeon/pubspec.yaml
index 616b1a5e5a..8e7b9f0369 100644
--- a/packages/pigeon/pubspec.yaml
+++ b/packages/pigeon/pubspec.yaml
@@ -1,5 +1,5 @@
 name: pigeon
-version: 0.1.3
+version: 0.1.4
 description: Code generator tool to make communication between Flutter and the host platform type-safe and easier.
 homepage: https://github.com/flutter/packages/tree/master/packages/pigeon
 dependencies:
diff --git a/packages/pigeon/test/dart_generator_test.dart b/packages/pigeon/test/dart_generator_test.dart
index 0089145885..296b275c1c 100644
--- a/packages/pigeon/test/dart_generator_test.dart
+++ b/packages/pigeon/test/dart_generator_test.dart
@@ -58,7 +58,10 @@ void main() {
     final StringBuffer sink = StringBuffer();
     generateDart(root, sink);
     final String code = sink.toString();
-    expect(code, contains('pigeonMap[\'nested\'] = nested._toMap()'));
+    expect(
+        code,
+        contains(
+            'pigeonMap[\'nested\'] = nested == null ? null : nested._toMap()'));
     expect(code,
         contains('result.nested = Input._fromMap(pigeonMap[\'nested\']);'));
   });
diff --git a/packages/pigeon/test/objc_generator_test.dart b/packages/pigeon/test/objc_generator_test.dart
index 74ade0fdfe..1acbcc5680 100644
--- a/packages/pigeon/test/objc_generator_test.dart
+++ b/packages/pigeon/test/objc_generator_test.dart
@@ -315,7 +315,7 @@ void main() {
     final StringBuffer sink = StringBuffer();
     generateObjcHeader(ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
     final String code = sink.toString();
-    expect(code, contains('completion:(void(^)(NSError*))'));
+    expect(code, contains('completion:(void(^)(NSError* _Nullable))'));
   });
 
   test('gen flutter void return source', () {
@@ -331,7 +331,7 @@ void main() {
     final StringBuffer sink = StringBuffer();
     generateObjcSource(ObjcOptions(header: 'foo.h', prefix: 'ABC'), root, sink);
     final String code = sink.toString();
-    expect(code, contains('completion:(void(^)(NSError*))'));
+    expect(code, contains('completion:(void(^)(NSError* _Nullable))'));
     expect(code, contains('completion(nil)'));
   });
 
@@ -383,7 +383,7 @@ void main() {
     expect(
         code,
         contains(
-            '(void)doSomething:(void(^)(ABCOutput*, NSError*))completion'));
+            '(void)doSomething:(void(^)(ABCOutput*, NSError* _Nullable))completion'));
   });
 
   test('gen flutter void arg header', () {
@@ -402,7 +402,7 @@ void main() {
     expect(
         code,
         contains(
-            '(void)doSomething:(void(^)(ABCOutput*, NSError*))completion'));
+            '(void)doSomething:(void(^)(ABCOutput*, NSError* _Nullable))completion'));
     expect(code, contains('channel sendMessage:nil'));
   });
 
diff --git a/packages/pigeon/test/version_test.dart b/packages/pigeon/test/version_test.dart
new file mode 100644
index 0000000000..70e4382a12
--- /dev/null
+++ b/packages/pigeon/test/version_test.dart
@@ -0,0 +1,19 @@
+// Copyright 2020 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:io';
+
+import 'package:pigeon/generator_tools.dart';
+import 'package:test/test.dart';
+
+void main() {
+  test('pigeon version matches pubspec', () {
+    final String pubspecPath = '${Directory.current.path}/pubspec.yaml';
+    final String pubspec = File(pubspecPath).readAsStringSync();
+    final RegExp regex = RegExp('version:\s*(.*)');
+    final RegExpMatch match = regex.firstMatch(pubspec);
+    expect(match, isNotNull);
+    expect(pigeonVersion, match.group(1).trim());
+  });
+}