diff --git a/CHANGELOG.md b/CHANGELOG.md
index c05e6282..6e80bec1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,37 @@
 Changelog
 =========
 
+## 2.9.4 (2018-05-02)
+
+* Enable nativeSerializer to handle Error objects by extracting the stack and message from a given Error class before serialising it. [#239](https://github.com/bugsnag/bugsnag-react-native/issues/239) [#240](https://github.com/bugsnag/bugsnag-react-native/pull/240) [daisy1754](https://github.com/daisy1754) [Cawllec](https://github.com/Cawllec)
+
+* Upgrade bugsnag-android to v4.3.4:
+  - *Bug Fixes:*
+    - Avoid adding extra comma separator in JSON if File input is empty or null [#284](https://github.com/bugsnag/bugsnag-android/pull/284)
+    - Thread safety fixes to JSON file serialisation [#295](https://github.com/bugsnag/bugsnag-android/pull/295)
+    - Prevent potential automatic activity lifecycle breadcrumb crash [#300](https://github.com/bugsnag/bugsnag-android/pull/300)
+    - Fix serialisation issue with leading to incorrect dashboard display of breadcrumbs [#306](https://github.com/bugsnag/bugsnag-android/pull/306)
+    - Prevent duplicate reports being delivered in low connectivity situations [#270](https://github.com/bugsnag/bugsnag-android/pull/270)
+    - Fix possible NPE when reading default metadata filters [#263](https://github.com/bugsnag/bugsnag-android/pull/263)
+    - Prevent ConcurrentModificationException in Before notify/breadcrumb callbacks [#266](https://github.com/bugsnag/bugsnag-android/pull/266)
+    - Ensure that exception message is never null [#256](https://github.com/bugsnag/bugsnag-android/pull/256)
+    - Add payload version to JSON body [#244](https://github.com/bugsnag/bugsnag-android/pull/244)
+    - Update context tracking to use lifecycle callbacks rather than ActivityManager [#238](https://github.com/bugsnag/bugsnag-android/pull/238)
+  - *Enhancements:*
+    - Detect whether running on emulator [#245](https://github.com/bugsnag/bugsnag-android/pull/245)
+    - Add a callback for filtering breadcrumbs [#237](https://github.com/bugsnag/bugsnag-android/pull/237)
+* Upgrade bugsnag-cocoa to v5.15.5:
+  - *Bug Fixes:*
+    - Changes report generation so that when a minimal or incomplete crash is recorded, essential app/device information is included in the report on the next application launch. [#239](https://github.com/bugsnag/bugsnag-cocoa/pull/239)
+  [#250](https://github.com/bugsnag/bugsnag-cocoa/pull/250)
+    - Ensure timezone is serialised in report payload.
+  [#248](https://github.com/bugsnag/bugsnag-cocoa/pull/248)
+    - Ensure error class and message are persisted when thread tracing is disabled [#245](https://github.com/bugsnag/bugsnag-cocoa/pull/245)
+    - Re-addapp name to the app tab of reports [#244](https://github.com/bugsnag/bugsnag-cocoa/pull/244)
+    - Add payload version to report body to preserve backwards compatibility with older versions of the error reporting API [#241](https://github.com/bugsnag/bugsnag-cocoa/pull/241)
+  - *Enhancements:*
+    -This release adds additional device metadata for filtering by whether an error occurred in a simulator ([#242](https://github.com/bugsnag/bugsnag-cocoa/pull/242)) and by processor word size ([#228](https://github.com/bugsnag/bugsnag-cocoa/pull/228)).
+
 ## 2.9.3 (2018-03-16)
 
 ### Bug Fixes
diff --git a/README.md b/README.md
index f62e3098..917575b2 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 # Bugsnag exception reporter for React Native
-[![Documentation](https://img.shields.io/badge/documentation-2.9.3-blue.svg)](http://docs.bugsnag.com/platforms/react-native/)
+[![Documentation](https://img.shields.io/badge/documentation-2.9.4-blue.svg)](http://docs.bugsnag.com/platforms/react-native/)
 
 Automatic [React Native crash reporting](https://www.bugsnag.com/platforms/react-native-error-reporting/) with Bugsnag helps you detect both native OS and JavaScript errors in your React Native apps.
 
diff --git a/android/build.gradle b/android/build.gradle
index 6f32b0fb..e88bcb43 100644
--- a/android/build.gradle
+++ b/android/build.gradle
@@ -8,11 +8,11 @@ android {
         minSdkVersion 16
         targetSdkVersion 23
         versionCode 4
-        versionName '2.9.3'
+        versionName '2.9.4'
     }
 }
 
 dependencies {
-    compile 'com.bugsnag:bugsnag-android:4.3.1'
+    compile 'com.bugsnag:bugsnag-android:4.3.4'
     compile 'com.facebook.react:react-native:+'
 }
diff --git a/cocoa/vendor/bugsnag-cocoa/Source/BugsnagCrashReport.m b/cocoa/vendor/bugsnag-cocoa/Source/BugsnagCrashReport.m
index 42e313aa..090cd669 100644
--- a/cocoa/vendor/bugsnag-cocoa/Source/BugsnagCrashReport.m
+++ b/cocoa/vendor/bugsnag-cocoa/Source/BugsnagCrashReport.m
@@ -483,7 +483,10 @@ - (NSDictionary *)toJson {
     
     NSMutableDictionary *appObj = [NSMutableDictionary new];
     [appObj addEntriesFromDictionary:self.app];
-    [appObj addEntriesFromDictionary:self.appState];
+    
+    for (NSString *key in self.appState) {
+        BSGDictInsertIfNotNil(appObj, self.appState[key], key);
+    }
     
     if (self.dsymUUID) {
         BSGDictInsertIfNotNil(appObj, @[self.dsymUUID], @"dsymUUIDs");
diff --git a/cocoa/vendor/bugsnag-cocoa/Source/BugsnagKSCrashSysInfoParser.m b/cocoa/vendor/bugsnag-cocoa/Source/BugsnagKSCrashSysInfoParser.m
index aa8f143c..ff632ccc 100644
--- a/cocoa/vendor/bugsnag-cocoa/Source/BugsnagKSCrashSysInfoParser.m
+++ b/cocoa/vendor/bugsnag-cocoa/Source/BugsnagKSCrashSysInfoParser.m
@@ -13,6 +13,8 @@
 #import "BugsnagConfiguration.h"
 #import "BugsnagLogger.h"
 
+#define PLATFORM_WORD_SIZE sizeof(void*)*8
+
 NSDictionary *BSGParseDevice(NSDictionary *report) {
     NSMutableDictionary *device =
     [[report valueForKeyPath:@"user.state.deviceState"] mutableCopy];
@@ -22,7 +24,7 @@
     BSGDictSetSafeObject(device, [[NSLocale currentLocale] localeIdentifier],
                          @"locale");
     
-    BSGDictSetSafeObject(device, report[@"time_zone"], @"timezone");
+    BSGDictSetSafeObject(device, [report valueForKeyPath:@"system.time_zone"], @"timezone");
     BSGDictSetSafeObject(device, [report valueForKeyPath:@"system.memory.usable"],
                          @"totalMemory");
     
@@ -47,6 +49,13 @@
     NSNumber *freeBytes = [fileSystemAttrs objectForKey:NSFileSystemFreeSize];
     BSGDictSetSafeObject(device, freeBytes, @"freeDisk");
     BSGDictSetSafeObject(device, report[@"system"][@"device_app_hash"], @"id");
+
+#if TARGET_OS_SIMULATOR
+    BSGDictSetSafeObject(device, @YES, @"simulator");
+#elif TARGET_OS_IPHONE || TARGET_OS_TV
+    BSGDictSetSafeObject(device, @NO, @"simulator");
+#endif
+
     return device;
 }
 
@@ -62,6 +71,8 @@
     
     BSGDictSetSafeObject(appState, @(activeTimeSinceLaunch),
                          @"durationInForeground");
+
+    BSGDictSetSafeObject(appState, report[BSGKeyExecutableName], BSGKeyName);
     BSGDictSetSafeObject(appState,
                          @(activeTimeSinceLaunch + backgroundTimeSinceLaunch),
                          @"duration");
@@ -103,6 +114,7 @@
     BSGDictSetSafeObject(deviceState, report[@"machine"], @"model");
     BSGDictSetSafeObject(deviceState, report[@"system_name"], @"osName");
     BSGDictSetSafeObject(deviceState, report[@"system_version"], @"osVersion");
+    BSGDictSetSafeObject(deviceState, @(PLATFORM_WORD_SIZE), @"wordSize");
     BSGDictSetSafeObject(deviceState, @"Apple", @"manufacturer");
     BSGDictSetSafeObject(deviceState, report[@"jailbroken"], @"jailbroken");
     return deviceState;
diff --git a/cocoa/vendor/bugsnag-cocoa/Source/BugsnagNotifier.m b/cocoa/vendor/bugsnag-cocoa/Source/BugsnagNotifier.m
index 1eb71722..8687fb43 100644
--- a/cocoa/vendor/bugsnag-cocoa/Source/BugsnagNotifier.m
+++ b/cocoa/vendor/bugsnag-cocoa/Source/BugsnagNotifier.m
@@ -41,7 +41,7 @@
 #import <AppKit/AppKit.h>
 #endif
 
-NSString *const NOTIFIER_VERSION = @"5.15.3";
+NSString *const NOTIFIER_VERSION = @"5.15.5";
 NSString *const NOTIFIER_URL = @"https://github.com/bugsnag/bugsnag-cocoa";
 NSString *const BSTabCrash = @"crash";
 NSString *const BSAttributeDepth = @"depth";
diff --git a/cocoa/vendor/bugsnag-cocoa/Source/BugsnagSink.m b/cocoa/vendor/bugsnag-cocoa/Source/BugsnagSink.m
index a95d9558..0fc2517a 100644
--- a/cocoa/vendor/bugsnag-cocoa/Source/BugsnagSink.m
+++ b/cocoa/vendor/bugsnag-cocoa/Source/BugsnagSink.m
@@ -29,6 +29,7 @@
 #import "BugsnagCollections.h"
 #import "BugsnagNotifier.h"
 #import "BugsnagKeys.h"
+#import "BSG_KSSystemInfo.h"
 
 // This is private in Bugsnag, but really we want package private so define
 // it here.
@@ -59,9 +60,40 @@ - (void)filterReports:(NSArray *)reports
          onCompletion:(BSG_KSCrashReportFilterCompletion)onCompletion {
     NSMutableArray *bugsnagReports = [NSMutableArray new];
     BugsnagConfiguration *configuration = [Bugsnag configuration];
+    
     for (NSDictionary *report in reports) {
-        BugsnagCrashReport *bugsnagReport =
-                [[BugsnagCrashReport alloc] initWithKSReport:report];
+        BugsnagCrashReport *bugsnagReport = [[BugsnagCrashReport alloc] initWithKSReport:report];
+        BOOL incompleteReport = (![@"standard" isEqualToString:[report valueForKeyPath:@"report.type"]] ||
+                                 [[report objectForKey:@"incomplete"] boolValue]);
+        
+        if (incompleteReport) { // append app/device data as this is unlikely to change between sessions
+            NSDictionary *sysInfo = [BSG_KSSystemInfo systemInfo];
+            
+            // reset any existing data as it will be corrupted/nil
+            bugsnagReport.appState = @{};
+            bugsnagReport.deviceState = @{};
+
+
+            NSMutableDictionary *appDict = [NSMutableDictionary new];
+            BSGDictInsertIfNotNil(appDict, sysInfo[@BSG_KSSystemField_BundleVersion], @"bundleVersion");
+            BSGDictInsertIfNotNil(appDict, sysInfo[@BSG_KSSystemField_BundleID], @"id");
+            BSGDictInsertIfNotNil(appDict, configuration.releaseStage, @"releaseStage");
+            BSGDictInsertIfNotNil(appDict, sysInfo[@BSG_KSSystemField_SystemName], @"type");
+            BSGDictInsertIfNotNil(appDict, sysInfo[@BSG_KSSystemField_BundleShortVersion], @"version");
+
+            NSMutableDictionary *deviceDict = [NSMutableDictionary new];
+            BSGDictInsertIfNotNil(deviceDict, sysInfo[@BSG_KSSystemField_Jailbroken], @"jailbroken");
+            BSGDictInsertIfNotNil(deviceDict, [[NSLocale currentLocale] localeIdentifier], @"locale");
+            BSGDictInsertIfNotNil(deviceDict, sysInfo[@"Apple"], @"manufacturer");
+            BSGDictInsertIfNotNil(deviceDict, sysInfo[@BSG_KSSystemField_Machine], @"model");
+            BSGDictInsertIfNotNil(deviceDict, sysInfo[@BSG_KSSystemField_Model], @"modelNumber");
+            BSGDictInsertIfNotNil(deviceDict, sysInfo[@BSG_KSSystemField_SystemName], @"osName");
+            BSGDictInsertIfNotNil(deviceDict, sysInfo[@BSG_KSSystemField_SystemVersion], @"osVersion");
+
+            bugsnagReport.app = appDict;
+            bugsnagReport.device = deviceDict;
+        }
+        
         if (![bugsnagReport shouldBeSent])
             continue;
         BOOL shouldSend = YES;
@@ -115,6 +147,7 @@ - (NSDictionary *)getBodyFromReports:(NSArray *)reports {
     NSMutableDictionary *data = [[NSMutableDictionary alloc] init];
     BSGDictSetSafeObject(data, [Bugsnag notifier].details, BSGKeyNotifier);
     BSGDictSetSafeObject(data, [Bugsnag notifier].configuration.apiKey, BSGKeyApiKey);
+    BSGDictSetSafeObject(data, @"4.0", @"payloadVersion");
 
     NSMutableArray *formatted =
             [[NSMutableArray alloc] initWithCapacity:[reports count]];
diff --git a/cocoa/vendor/bugsnag-cocoa/Source/KSCrash/Source/KSCrash/Recording/BSG_KSCrashReport.c b/cocoa/vendor/bugsnag-cocoa/Source/KSCrash/Source/KSCrash/Recording/BSG_KSCrashReport.c
index 6693fbfb..6c9da5cd 100644
--- a/cocoa/vendor/bugsnag-cocoa/Source/KSCrash/Source/KSCrash/Recording/BSG_KSCrashReport.c
+++ b/cocoa/vendor/bugsnag-cocoa/Source/KSCrash/Source/KSCrash/Recording/BSG_KSCrashReport.c
@@ -2084,9 +2084,9 @@ void bsg_kscrashreport_writeStandardReport(
                     crashContext->config.introspectionRules.enabled,
                     crashContext->config.searchThreadNames,
                     crashContext->config.searchQueueNames);
-                bsg_kscrw_i_writeError(writer, BSG_KSCrashField_Error,
-                                       &crashContext->crash);
             }
+            bsg_kscrw_i_writeError(writer, BSG_KSCrashField_Error,
+                    &crashContext->crash);
         }
         writer->endContainer(writer);
 
diff --git a/package.json b/package.json
index 1f564457..86491d7d 100644
--- a/package.json
+++ b/package.json
@@ -3,12 +3,13 @@
   "homepage": "https://www.bugsnag.com/platforms/react-native-error-reporting/",
   "repository": "https://github.com/bugsnag/bugsnag-react-native.git",
   "bugs": "https://github.com/bugsnag/bugsnag-react-native/issues",
-  "version": "2.9.3",
+  "version": "2.9.4",
   "license": "MIT",
   "main": "index.js",
   "types": "index.d.ts",
   "nativePackage": true,
   "dependencies": {
+    "iserror": "^0.0.2",
     "promise": "^7",
     "prop-types": "^15.6.0"
   },
diff --git a/src/NativeSerializer.js b/src/NativeSerializer.js
index d1de5a39..25943276 100644
--- a/src/NativeSerializer.js
+++ b/src/NativeSerializer.js
@@ -1,3 +1,5 @@
+const isError = require('iserror')
+
 const allowedMapObjectTypes = [ 'string', 'number', 'boolean' ]
 
 /**
@@ -7,6 +9,9 @@ const allowedMapObjectTypes = [ 'string', 'number', 'boolean' ]
 const serializeForNativeLayer = (map, maxDepth = 10, depth = 0, seen = new Set()) => {
   seen.add(map)
   const output = {}
+  if (isError(map)) {
+    map = extractErrorDetails(map)
+  }
   for (const key in map) {
     if (!{}.hasOwnProperty.call(map, key)) continue
 
@@ -35,4 +40,9 @@ const serializeForNativeLayer = (map, maxDepth = 10, depth = 0, seen = new Set()
   return output
 }
 
-export default serializeForNativeLayer
+const extractErrorDetails = (err) => {
+  const { message, stack, name } = err
+  return { message, stack, name }
+}
+
+module.exports = serializeForNativeLayer
diff --git a/src/__tests__/NativeSerializer.test.js b/src/__tests__/NativeSerializer.test.js
index 6bd38b83..f441a945 100644
--- a/src/__tests__/NativeSerializer.test.js
+++ b/src/__tests__/NativeSerializer.test.js
@@ -134,3 +134,18 @@ test('serializeForNativeLayer handles deep nesting', () => {
     }
   })
 })
+
+test('serializeForNativeLayer handles error objects', () => {
+  const err = new Error('Oh no')
+  const serialized = serializeForNativeLayer(err)
+  expect(serialized['message']).toEqual({
+    type: 'string',
+    value: 'Oh no'
+  })
+  expect(serialized['stack']['type']).toEqual('string')
+  expect(serialized['stack']['value'].length).toBeGreaterThan(0)
+  expect(serialized['name']).toEqual({
+    type: 'string',
+    value: 'Error'
+  })
+})
diff --git a/yarn.lock b/yarn.lock
index d6b33121..078fd665 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2206,6 +2206,10 @@ isarray@1.0.0, isarray@^1.0.0, isarray@~1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/isarray/-/isarray-1.0.0.tgz#bb935d48582cba168c06834957a54a3e07124f11"
 
+iserror@^0.0.2:
+  version "0.0.2"
+  resolved "https://registry.yarnpkg.com/iserror/-/iserror-0.0.2.tgz#bd53451fe2f668b9f2402c1966787aaa2c7c0bf5"
+
 isexe@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/isexe/-/isexe-2.0.0.tgz#e8fbf374dc556ff8947a10dcb0572d633f2cfa10"