                             moc.delete(entry)
                         }
                         
+                        if sinceDate.compare(Date.distantPast) != .orderedSame {
+                            let iso8601String = DateFormatter.wmf_iso8601().string(from: sinceDate)
+                            moc.wmf_setValue(iso8601String as NSString, forKey: WMFReadingListUpdateKey)
+                        }
+                        
                         guard moc.hasChanges else {
                             return
                         }

                remoteReadingListsByID[apiReadingList.id] = apiReadingList
                remoteReadingListsToCreateLocally[apiReadingList.id] = apiReadingList
                remoteReadingListsByName[apiReadingList.name.precomposedStringWithCanonicalMapping] = apiReadingList
            }
            DispatchQueue.main.async {
                self.dataStore.performBackgroundCoreDataOperation(onATemporaryContext: { (moc) in

                self.finish(with: error)
                return
            }
            var sinceDate: Date = Date.distantPast
            var remoteReadingListsByID: [Int64: APIReadingList] = [:]
            var remoteReadingListsToCreateLocally: [Int64: APIReadingList] = [:]
            var remoteReadingListsByName: [String: APIReadingList] = [:]
