Refactoring: Improved ExternalSync source name for Exchange.

db/migrate/20180108000001_change_exchange_external_sync_identifier.rb

@@ -0,0 +1,10 @@
+class ChangeExchangeExternalSyncIdentifier < ActiveRecord::Migration[5.1]
+  def up
+    # return if it's a new setup to avoid running the migration
+    return if !Setting.find_by(name: 'system_init_done')
+
+    # rubocop:disable Rails/SkipsModelValidations
+    ExternalSync.where(source: 'EWS::FolderContact').update_all(source: 'Exchange::FolderContact')
+  end
+
+end

lib/sequencer/unit/import/exchange/folder_contact/static_attributes.rb

@@ -9,7 +9,7 @@ class Sequencer
 
             def process
               state.provide(:model_class, ::User)
-              state.provide(:external_sync_source, 'EWS::FolderContact')
+              state.provide(:external_sync_source, 'Exchange::FolderContact')
             end
           end
         end