zammad/db/migrate/20180108000001_change_exchange_external_sync_identifier.rb

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