diff --git a/CHANGELOG.md b/CHANGELOG.md
index cb5fee60..d64fedd8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,12 +1,12 @@
-x.x.x Release notes (yyyy-MM-dd)
 =============================================================
 ### Enhancements
 * None.
 
 ### Fixed
-* <How to hit and notice issue? what was the impact?> ([#????](https://github.com/realm/realm-js/issues/????), since v?.?.?)
-* Removed calls to `new Buffer()` as this is deprecated with Node 10. ([#2107](https://github.com/realm/realm-js/issues/2107), since 2.19.0)
-* Updated the type definitions to be explicit that the return type of the generics `Realm.objects<T>`, `Realm.objectForPrimaryKey<T>`, etc. is an intersection of `T & Realm.Object`. ([#1838](https://github.com/realm/realm-js/issues/1838))
+* The Typescript definition for `Realm.Permissions.Permission` did not have the correct `role` property defined. This could result in compilation errors like this `error TS2339: Property 'role' does not exist on type 'Permission'`. ([#2106](https://github.com/realm/realm-js/pull/2106), since v2.3.0.)
+* Removes calls to `new Buffer()` as this is deprecated with Node 10. ([#2107](https://github.com/realm/realm-js/issues/2107), since v2.19.0)
+* Updates the type definitions to be explicit that the return type of the generics `Realm.objects<T>`, `Realm.objectForPrimaryKey<T>`, etc. is an intersection of `T & Realm.Object`. ([#1838](https://github.com/realm/realm-js/issues/1838))
+* A set of bugs that could lead to bad changesets have been fixed. An example of error message is `Failed to parse, or apply received changeset: ndx out of range`. (Fixed by Realm Sync v3.13.3)
 
 ### Compatibility
 * Realm Object Server: 3.11.0 or later.
@@ -14,25 +14,11 @@ x.x.x Release notes (yyyy-MM-dd)
 * File format: Generates Realms with format v9 (Reads and upgrades all previous formats)
 
  ### Internal
-* Introduce 100 ms delay before submitting analytics so that an app may disable it after importing Realm. ([#2108](https://github.com/realm/realm-js/pull/2108))
+* Introduces 100 ms delay before submitting analytics so that an app may disable it after importing Realm. ([#2108](https://github.com/realm/realm-js/pull/2108))
 * Distinguish between node.js and electron in the `BindingType` field when submitting analytics. ([#2108](https://github.com/realm/realm-js/pull/2108))
-* Add a package to compute the Windows analytics identifier rather than returning `null` which likely accounts for the disproportionally large number of unique Windows users. ([#2108](https://github.com/realm/realm-js/pull/2108))
-
-x.x.x Release notes (yyyy-MM-dd)
-=============================================================
-### Enhancements
-* None.
-
-### Fixed
-* The Typescript definition for `Realm.Permissions.Permission` did not have the correct `role` property defined. This could result in compilation errors like this "error TS2339: Property 'role' does not exist on type 'Permission'". Since 2.3.0. ([#2106](https://github.com/realm/realm-js/pull/2106))
-
-### Compatibility
-* Realm Object Server: 3.11.0 or later.
-* APIs are backwards compatible with all previous release of realm in the 2.x.y series.
-* File format: Generates Realms with format v9 (Reads and upgrades all previous formats)
-
- ### Internal
-* None.
+* Adds a package to compute the Windows analytics identifier rather than returning `null` which likely accounts for the disproportionally large number of unique Windows users. ([#2108](https://github.com/realm/realm-js/pull/2108))
+* Upgrades to Realm Core v5.12.1.
+* Upgrades to Realm Sync v3.13.3.
 
 2.19.0 Release notes (2018-11-8)
 =============================================================
diff --git a/dependencies.list b/dependencies.list
index dc18b92d..0cabe467 100644
--- a/dependencies.list
+++ b/dependencies.list
@@ -1,5 +1,5 @@
 PACKAGE_NAME=realm-js
 VERSION=2.19.0
-REALM_CORE_VERSION=5.12.0
-REALM_SYNC_VERSION=3.13.1
+REALM_CORE_VERSION=5.12.1
+REALM_SYNC_VERSION=3.13.3
 REALM_OBJECT_SERVER_VERSION=3.11.1
diff --git a/src/js_object_accessor.hpp b/src/js_object_accessor.hpp
index 55c96128..2498c5b1 100644
--- a/src/js_object_accessor.hpp
+++ b/src/js_object_accessor.hpp
@@ -85,7 +85,7 @@ public:
     }
 
     template<typename T>
-    T unbox(ValueType value, bool create = false, bool update = false);
+    T unbox(ValueType value, bool create = false, bool update = false, bool only_update_diff_objects = false, size_t current_row = realm::npos);
 
     template<typename T>
     util::Optional<T> unbox_optional(ValueType value) {
@@ -171,63 +171,63 @@ private:
 namespace _impl {
 template<typename JSEngine>
 struct Unbox<JSEngine, bool> {
-    static bool call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool) {
+    static bool call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool, bool, size_t) {
         return js::Value<JSEngine>::validated_to_boolean(ctx->m_ctx, value, "Property");
     }
 };
 
 template<typename JSEngine>
 struct Unbox<JSEngine, int64_t> {
-    static int64_t call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool) {
+    static int64_t call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool, bool, size_t) {
         return js::Value<JSEngine>::validated_to_number(ctx->m_ctx, value, "Property");
     }
 };
 
 template<typename JSEngine>
 struct Unbox<JSEngine, float> {
-    static float call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool) {
+    static float call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool, bool, size_t) {
         return js::Value<JSEngine>::validated_to_number(ctx->m_ctx, value, "Property");
     }
 };
 
 template<typename JSEngine>
 struct Unbox<JSEngine, double> {
-    static double call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool) {
+    static double call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool, bool, size_t) {
         return js::Value<JSEngine>::validated_to_number(ctx->m_ctx, value, "Property");
     }
 };
 
 template<typename JSEngine>
 struct Unbox<JSEngine, util::Optional<bool>> {
-    static util::Optional<bool> call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool) {
+    static util::Optional<bool> call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool, bool, size_t) {
         return ctx->template unbox_optional<bool>(value);
 }
 };
 
 template<typename JSEngine>
 struct Unbox<JSEngine, util::Optional<int64_t>> {
-    static util::Optional<int64_t> call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool) {
+    static util::Optional<int64_t> call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool, bool, size_t) {
         return ctx->template unbox_optional<int64_t>(value);
 }
 };
 
 template<typename JSEngine>
 struct Unbox<JSEngine, util::Optional<float>> {
-    static util::Optional<float> call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool) {
+    static util::Optional<float> call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool, bool, size_t) {
         return ctx->template unbox_optional<float>(value);
 }
 };
 
 template<typename JSEngine>
 struct Unbox<JSEngine, util::Optional<double>> {
-    static util::Optional<double> call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool) {
+    static util::Optional<double> call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool, bool, size_t) {
         return ctx->template unbox_optional<double>(value);
 }
 };
 
 template<typename JSEngine>
 struct Unbox<JSEngine, StringData> {
-    static StringData call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool) {
+    static StringData call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool, bool, size_t) {
         if (ctx->is_null(value)) {
             return StringData();
         }
@@ -238,7 +238,7 @@ struct Unbox<JSEngine, StringData> {
 
 template<typename JSEngine>
 struct Unbox<JSEngine, BinaryData> {
-    static BinaryData call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value value, bool, bool) {
+    static BinaryData call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value value, bool, bool, bool, size_t) {
         if (ctx->is_null(value)) {
             return BinaryData();
         }
@@ -265,14 +265,14 @@ struct Unbox<JSEngine, BinaryData> {
 
 template<typename JSEngine>
 struct Unbox<JSEngine, Mixed> {
-    static Mixed call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool) {
+    static Mixed call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool, bool, size_t) {
         throw std::runtime_error("'Any' type is unsupported");
     }
 };
 
 template<typename JSEngine>
 struct Unbox<JSEngine, Timestamp> {
-    static Timestamp call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool) {
+    static Timestamp call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool, bool, bool, size_t) {
         if (ctx->is_null(value)) {
             return Timestamp();
         }
@@ -293,7 +293,7 @@ struct Unbox<JSEngine, Timestamp> {
 
 template<typename JSEngine>
 struct Unbox<JSEngine, RowExpr> {
-    static RowExpr call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool create, bool try_update) {
+    static RowExpr call(NativeAccessor<JSEngine> *ctx, typename JSEngine::Value const& value, bool create, bool try_update, bool only_update_diffed, size_t current_row) {
         using Value = js::Value<JSEngine>;
         using ValueType = typename JSEngine::Value;
 
@@ -316,7 +316,7 @@ struct Unbox<JSEngine, RowExpr> {
         }
 
         auto child = realm::Object::create<ValueType>(*ctx, ctx->m_realm, *ctx->m_object_schema,
-                                                      static_cast<ValueType>(object), try_update);
+                                                      static_cast<ValueType>(object), try_update, only_update_diffed, current_row);
         return child.row();
     }
 };
@@ -324,8 +324,8 @@ struct Unbox<JSEngine, RowExpr> {
 
 template<typename T>
 template<typename U>
-U NativeAccessor<T>::unbox(ValueType value, bool create, bool update) {
-    return _impl::Unbox<T, U>::call(this, std::move(value), create, update);
+U NativeAccessor<T>::unbox(ValueType value, bool create, bool update, bool only_update_diff_objects, size_t current_row) {
+    return _impl::Unbox<T, U>::call(this, std::move(value), create, update, only_update_diff_objects, current_row);
 }
 
 template<typename T>
diff --git a/src/js_realm.cpp b/src/js_realm.cpp
index 687603aa..c2bcbf4c 100644
--- a/src/js_realm.cpp
+++ b/src/js_realm.cpp
@@ -59,7 +59,7 @@ void clear_test_state() {
         user->log_out();
     }
     SyncManager::shared().reset_for_testing();
-    SyncManager::shared().configure_file_system(default_realm_file_directory(), SyncManager::MetadataMode::NoEncryption);
+    SyncManager::shared().configure(default_realm_file_directory(), SyncManager::MetadataMode::NoEncryption);
 #endif
 }
 
diff --git a/src/js_realm.hpp b/src/js_realm.hpp
index 1e548f13..69520807 100644
--- a/src/js_realm.hpp
+++ b/src/js_realm.hpp
@@ -949,12 +949,13 @@ void RealmClass<T>::create(ContextType ctx, ObjectType this_object, Arguments &a
     }
 
     bool update = false;
+    bool only_update_diff_objects = false;
     if (args.count == 3) {
         update = Value::validated_to_boolean(ctx, args[2], "update");
     }
 
     NativeAccessor accessor(ctx, realm, object_schema);
-    auto realm_object = realm::Object::create<ValueType>(accessor, realm, object_schema, object, update);
+    auto realm_object = realm::Object::create<ValueType>(accessor, realm, object_schema, object, update, only_update_diff_objects);
     return_value.set(RealmObjectClass<T>::create_instance(ctx, std::move(realm_object)));
 }
 
diff --git a/src/js_sync.hpp b/src/js_sync.hpp
index 569ad312..fafeca10 100644
--- a/src/js_sync.hpp
+++ b/src/js_sync.hpp
@@ -48,7 +48,7 @@ inline realm::SyncManager& syncManagerShared() {
     static std::once_flag flag;
     std::call_once(flag, [] {
         ensure_directory_exists_for_file(default_realm_file_directory());
-        SyncManager::shared().configure_file_system(default_realm_file_directory(), SyncManager::MetadataMode::NoEncryption);
+        SyncManager::shared().configure(default_realm_file_directory(), SyncManager::MetadataMode::NoEncryption);
     });
     return SyncManager::shared();
 }
diff --git a/src/object-store b/src/object-store
index 362b8866..3253b505 160000
--- a/src/object-store
+++ b/src/object-store
@@ -1 +1 @@
-Subproject commit 362b886628b3aefc5b7a0bc32293d794dc1d4ad5
+Subproject commit 3253b5057573ee24e05d23b76505abb10e6deb32