diff --git a/Adjust.podspec b/Adjust.podspec
index 72e7a3825..ea5be490c 100644
--- a/Adjust.podspec
+++ b/Adjust.podspec
@@ -1,11 +1,11 @@
 Pod::Spec.new do |s|
   s.name           = "Adjust"
-  s.version        = "4.0.3"
+  s.version        = "4.0.4"
   s.summary        = "This is the iOS SDK of adjust. You can read more about it at http://adjust.com."
   s.homepage       = "http://adjust.com"
   s.license        = { :type => 'MIT', :file => 'MIT-LICENSE' }
   s.author         = { "Christian Wellenbrock" => "welle@adjust.com" }
-  s.source         = { :git => "https://github.com/adjust/ios_sdk.git", :tag => "v4.0.3" }
+  s.source         = { :git => "https://github.com/adjust/ios_sdk.git", :tag => "v4.0.4" }
   s.platform       = :ios, '4.3'
   s.framework      = 'SystemConfiguration'
   s.weak_framework = 'AdSupport', 'iAd'
diff --git a/Adjust/ADJActivityHandler.m b/Adjust/ADJActivityHandler.m
index 935f70e0c..9730d8ed8 100644
--- a/Adjust/ADJActivityHandler.m
+++ b/Adjust/ADJActivityHandler.m
@@ -193,6 +193,9 @@ - (BOOL)updateAttribution:(ADJAttribution *)attribution {
 }
 
 - (void)launchAttributionDelegate{
+    if (self.delegate == nil) {
+        return;
+    }
     if (![self.delegate respondsToSelector:@selector(adjustAttributionChanged:)]) {
         [self.logger warn:@"Delegate can't be launched because it does not implement AdjustDelegate"];
         return;
@@ -356,8 +359,6 @@ - (void)eventInternal:(ADJEvent *)event
     ADJPackageBuilder *eventBuilder = [[ADJPackageBuilder alloc] initWithDeviceInfo:self.deviceInfo
                                                                       activityState:self.activityState
                                                                              config:self.adjustConfig];
-    [self setIadDate:[NSDate date] withPurchaseDate:[NSDate date]];
-
     ADJActivityPackage *eventPackage = [eventBuilder buildEventPackage:event];
     [self.packageHandler addPackage:eventPackage];
 
@@ -480,6 +481,7 @@ - (void)writeAttribution {
 }
 
 - (void)readActivityState {
+    [NSKeyedUnarchiver setClass:[ADJActivityState class] forClassName:@"AIActivityState"];
     self.activityState = [ADJUtil readObject:kActivityStateFilename
                                   objectName:@"Activity state"
                                        class:[ADJActivityState class]];
diff --git a/Adjust/ADJActivityState.m b/Adjust/ADJActivityState.m
index f5e8ff287..8dd749dab 100644
--- a/Adjust/ADJActivityState.m
+++ b/Adjust/ADJActivityState.m
@@ -80,25 +80,33 @@ - (id)initWithCoder:(NSCoder *)decoder {
     self.timeSpent         = [decoder decodeDoubleForKey:@"timeSpent"];
     self.createdAt         = [decoder decodeDoubleForKey:@"createdAt"];
     self.lastActivity      = [decoder decodeDoubleForKey:@"lastActivity"];
-    self.uuid              = [decoder decodeObjectForKey:@"uuid"];
-    self.transactionIds    = [decoder decodeObjectForKey:@"transactionIds"];
-    self.enabled           = [decoder decodeBoolForKey:@"enabled"];
-    self.askingAttribution = [decoder decodeBoolForKey:@"askingAttribution"];
 
     // default values for migrating devices
+    if ([decoder containsValueForKey:@"uuid"]) {
+        self.uuid              = [decoder decodeObjectForKey:@"uuid"];
+    }
+
     if (self.uuid == nil) {
         self.uuid = [UIDevice.currentDevice adjCreateUuid];
     }
 
+    if ([decoder containsValueForKey:@"transactionIds"]) {
+        self.transactionIds    = [decoder decodeObjectForKey:@"transactionIds"];
+    }
+
     if (self.transactionIds == nil) {
         self.transactionIds = [NSMutableArray arrayWithCapacity:kTransactionIdCount];
     }
 
-    if (![decoder containsValueForKey:@"enabled"]) {
+    if ([decoder containsValueForKey:@"enabled"]) {
+        self.enabled           = [decoder decodeBoolForKey:@"enabled"];
+    } else {
         self.enabled = YES;
     }
 
-    if (![decoder containsValueForKey:@"askingAttribution"]) {
+    if ([decoder containsValueForKey:@"askingAttribution"]) {
+        self.askingAttribution = [decoder decodeBoolForKey:@"askingAttribution"];
+    } else {
         self.askingAttribution = NO;
     }
 
diff --git a/Adjust/ADJPackageHandler.m b/Adjust/ADJPackageHandler.m
index 306702d1b..5f3aaa9b5 100644
--- a/Adjust/ADJPackageHandler.m
+++ b/Adjust/ADJPackageHandler.m
@@ -140,6 +140,7 @@ - (void)sendNextInternal {
 #pragma mark - private
 - (void)readPackageQueue {
     @try {
+        [NSKeyedUnarchiver setClass:[ADJActivityPackage class] forClassName:@"AIActivityPackage"];
         NSString *filename = self.packageQueueFilename;
         id object = [NSKeyedUnarchiver unarchiveObjectWithFile:filename];
         if ([object isKindOfClass:[NSArray class]]) {
diff --git a/Adjust/ADJUtil.m b/Adjust/ADJUtil.m
index 518018d83..4a7fb6eb6 100644
--- a/Adjust/ADJUtil.m
+++ b/Adjust/ADJUtil.m
@@ -16,7 +16,7 @@
 #include <sys/xattr.h>
 
 static NSString * const kBaseUrl   = @"https://app.adjust.com";
-static NSString * const kClientSdk = @"ios4.0.3";
+static NSString * const kClientSdk = @"ios4.0.4";
 
 static NSString * const kDateFormat = @"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'Z";
 static NSDateFormatter *dateFormat;
@@ -24,6 +24,11 @@
 #pragma mark -
 @implementation ADJUtil
 
++ (void) initialize {
+    dateFormat = [[NSDateFormatter alloc] init];
+    [dateFormat setDateFormat:kDateFormat];
+}
+
 + (NSString *)baseUrl {
     return kBaseUrl;
 }
@@ -80,11 +85,6 @@ + (NSString *)formatSeconds1970:(double) value {
 
 
 + (NSString *)formatDate:(NSDate *) value {
-    if (dateFormat == nil) {
-        dateFormat = [[NSDateFormatter alloc] init];
-        [dateFormat setDateFormat:kDateFormat];
-    }
-
     return [dateFormat stringFromDate:value];
 }
 
diff --git a/AdjustTests/ADJActivityHandlerTests.m b/AdjustTests/ADJActivityHandlerTests.m
index 3244aa107..060fd3639 100644
--- a/AdjustTests/ADJActivityHandlerTests.m
+++ b/AdjustTests/ADJActivityHandlerTests.m
@@ -123,7 +123,7 @@ - (void)testFirstRun
     ADJActivityPackage *activityPackage = (ADJActivityPackage *) self.packageHandlerMock.packageQueue[0];
 
     //  check the Sdk version is being tested
-    XCTAssertEqual(@"ios4.0.3", activityPackage.clientSdk, @"%@", activityPackage.extendedString);
+    XCTAssertEqual(@"ios4.0.4", activityPackage.clientSdk, @"%@", activityPackage.extendedString);
 
     // check the server url
     XCTAssertEqual(@"https://app.adjust.com", ADJUtil.baseUrl);
@@ -177,9 +177,6 @@ - (void)testFirstRun
     //  has delegate
     XCTAssertEqual(1, [(NSString *)parameters[@"needs_attribution_data"] intValue], @"%@", activityPackage.extendedString);
 
-    //  network type
-    XCTAssertNotNil((NSString *)parameters[@"network_type"], @"%@", activityPackage.extendedString);
-
     //  os name
     XCTAssertEqual(@"ios", parameters[@"os_name"], @"%@", activityPackage.extendedString);
 
diff --git a/README.md b/README.md
index 533d286f2..d578ab77d 100644
--- a/README.md
+++ b/README.md
@@ -17,7 +17,7 @@ If you're using [CocoaPods][cocoapods], you can add the following line to your
 `Podfile` and continue with [step 3](#step3):
 
 ```ruby
-pod 'Adjust', :git => 'git://github.com/adjust/ios_sdk.git', :tag => 'v4.0.3'
+pod 'Adjust', :git => 'git://github.com/adjust/ios_sdk.git', :tag => 'v4.0.4'
 ```
 
 ### 1. Get the SDK
diff --git a/VERSION b/VERSION
index c4e41f945..c5106e6d1 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-4.0.3
+4.0.4
diff --git a/doc/migrate.md b/doc/migrate.md
index 70417fee8..dd21e6590 100644
--- a/doc/migrate.md
+++ b/doc/migrate.md
@@ -1,4 +1,4 @@
-## Migrate your adjust SDK for iOS to v4.0.3 from v3.4.0
+## Migrate your adjust SDK for iOS to v4.0.4 from v3.4.0
 
 ### Initial setup