diff --git a/modules/swagger-codegen/src/main/resources/objc/NSManagedObjectBuilder-body.mustache b/modules/swagger-codegen/src/main/resources/objc/NSManagedObjectBuilder-body.mustache
index 8bff47a1288..37df8840027 100644
--- a/modules/swagger-codegen/src/main/resources/objc/NSManagedObjectBuilder-body.mustache
+++ b/modules/swagger-codegen/src/main/resources/objc/NSManagedObjectBuilder-body.mustache
@@ -34,7 +34,13 @@
     if(!managedObject || !object) {
         return;
     }
-{{#vars}}{{^complexType}}    managedObject.{{name}} = [object.{{name}} copy];{{/complexType}}{{#complexType}}{{#isListContainer}}    if(object.{{name}}) {
+    NSManagedObjectContext* context = managedObject.managedObjectContext;
+{{#vars}}{{^complexType}}    managedObject.{{name}} = [object.{{name}} copy];{{/complexType}}{{#complexType}}{{#isListContainer}}    if(managedObject.{{name}}) {
+        for (id object in managedObject.{{name}}) {
+            [context deleteObject:object];
+        }
+    }
+    if(object.{{name}}) {
         NSMutableOrderedSet * convertedObjs = [NSMutableOrderedSet orderedSet];
         for (id innerObject in object.{{name}}) {
             id convertedObj = [self.{{name}}Builder {{complexType}}ManagedObjectFrom{{complexType}}:innerObject context:managedObject.managedObjectContext];
diff --git a/samples/client/petstore/objc/core-data/README.md b/samples/client/petstore/objc/core-data/README.md
index c3078b07594..115793a7bc5 100644
--- a/samples/client/petstore/objc/core-data/README.md
+++ b/samples/client/petstore/objc/core-data/README.md
@@ -6,6 +6,7 @@ This ObjC package is automatically generated by the [Swagger Codegen](https://gi
 
 - API version: 1.0.0
 - Package version: 
+- Build date: 2016-09-13T13:30:32.772+02:00
 - Build package: class io.swagger.codegen.languages.ObjcClientCodegen
 
 ## Requirements
diff --git a/samples/client/petstore/objc/core-data/SwaggerClient/Model/SWGCategoryManagedObjectBuilder.m b/samples/client/petstore/objc/core-data/SwaggerClient/Model/SWGCategoryManagedObjectBuilder.m
index 0672d46b217..02bcb34b815 100644
--- a/samples/client/petstore/objc/core-data/SwaggerClient/Model/SWGCategoryManagedObjectBuilder.m
+++ b/samples/client/petstore/objc/core-data/SwaggerClient/Model/SWGCategoryManagedObjectBuilder.m
@@ -32,6 +32,7 @@
     if(!managedObject || !object) {
         return;
     }
+    NSManagedObjectContext* context = managedObject.managedObjectContext;
     managedObject._id = [object._id copy];
     managedObject.name = [object.name copy];
 
diff --git a/samples/client/petstore/objc/core-data/SwaggerClient/Model/SWGOrderManagedObjectBuilder.m b/samples/client/petstore/objc/core-data/SwaggerClient/Model/SWGOrderManagedObjectBuilder.m
index 22244f0cf95..4345311f914 100644
--- a/samples/client/petstore/objc/core-data/SwaggerClient/Model/SWGOrderManagedObjectBuilder.m
+++ b/samples/client/petstore/objc/core-data/SwaggerClient/Model/SWGOrderManagedObjectBuilder.m
@@ -32,6 +32,7 @@
     if(!managedObject || !object) {
         return;
     }
+    NSManagedObjectContext* context = managedObject.managedObjectContext;
     managedObject._id = [object._id copy];
     managedObject.petId = [object.petId copy];
     managedObject.quantity = [object.quantity copy];
diff --git a/samples/client/petstore/objc/core-data/SwaggerClient/Model/SWGPetManagedObjectBuilder.m b/samples/client/petstore/objc/core-data/SwaggerClient/Model/SWGPetManagedObjectBuilder.m
index 13b4d0e6acf..5b5dc2bcab5 100644
--- a/samples/client/petstore/objc/core-data/SwaggerClient/Model/SWGPetManagedObjectBuilder.m
+++ b/samples/client/petstore/objc/core-data/SwaggerClient/Model/SWGPetManagedObjectBuilder.m
@@ -34,6 +34,7 @@
     if(!managedObject || !object) {
         return;
     }
+    NSManagedObjectContext* context = managedObject.managedObjectContext;
     managedObject._id = [object._id copy];
 
     if(!managedObject.category) {
@@ -43,6 +44,11 @@
     }
     managedObject.name = [object.name copy];
     managedObject.photoUrls = [object.photoUrls copy];
+    if(managedObject.tags) {
+        for (id object in managedObject.tags) {
+            [context deleteObject:object];
+        }
+    }
     if(object.tags) {
         NSMutableOrderedSet * convertedObjs = [NSMutableOrderedSet orderedSet];
         for (id innerObject in object.tags) {
diff --git a/samples/client/petstore/objc/core-data/SwaggerClient/Model/SWGTagManagedObjectBuilder.m b/samples/client/petstore/objc/core-data/SwaggerClient/Model/SWGTagManagedObjectBuilder.m
index 3c49ae2e49e..b4bcb4820ac 100644
--- a/samples/client/petstore/objc/core-data/SwaggerClient/Model/SWGTagManagedObjectBuilder.m
+++ b/samples/client/petstore/objc/core-data/SwaggerClient/Model/SWGTagManagedObjectBuilder.m
@@ -32,6 +32,7 @@
     if(!managedObject || !object) {
         return;
     }
+    NSManagedObjectContext* context = managedObject.managedObjectContext;
     managedObject._id = [object._id copy];
     managedObject.name = [object.name copy];
 
diff --git a/samples/client/petstore/objc/core-data/SwaggerClient/Model/SWGUserManagedObjectBuilder.m b/samples/client/petstore/objc/core-data/SwaggerClient/Model/SWGUserManagedObjectBuilder.m
index 72cefa95b89..9c981341ce8 100644
--- a/samples/client/petstore/objc/core-data/SwaggerClient/Model/SWGUserManagedObjectBuilder.m
+++ b/samples/client/petstore/objc/core-data/SwaggerClient/Model/SWGUserManagedObjectBuilder.m
@@ -32,6 +32,7 @@
     if(!managedObject || !object) {
         return;
     }
+    NSManagedObjectContext* context = managedObject.managedObjectContext;
     managedObject._id = [object._id copy];
     managedObject.username = [object.username copy];
     managedObject.firstName = [object.firstName copy];
diff --git a/samples/client/petstore/objc/default/README.md b/samples/client/petstore/objc/default/README.md
index c3078b07594..361040dadf0 100644
--- a/samples/client/petstore/objc/default/README.md
+++ b/samples/client/petstore/objc/default/README.md
@@ -6,6 +6,7 @@ This ObjC package is automatically generated by the [Swagger Codegen](https://gi
 
 - API version: 1.0.0
 - Package version: 
+- Build date: 2016-09-13T13:30:31.439+02:00
 - Build package: class io.swagger.codegen.languages.ObjcClientCodegen
 
 ## Requirements