Strategy for upgrading from v1.3.1 to v4 or v5?

I have an Ionic app that I built in 2017 that is version 1.3.1. Now, I need to make some enhancements to the app and upgrade it to Ionic v4 or v5. It’s not a complex app and doesn’t use any native device features: 6 pages/views, a few services to query data from the backend, and a single form.

Is there a common strategy for performing this upgrade of this magnitude? I have searched forums, and looked at the Ionic Migrations pages, but this is such a large jump that I haven’t found anything too useful.

Thanks.

/*!
 * Copyright 2015 Drifty Co.
 * http://drifty.com/
 *
 * Ionic, v1.3.1
 * A powerful HTML5 mobile app framework.
 * http://ionicframework.com/
 *
 * By @maxlynch, @benjsperry, @adamdbradley <3
 *
 * Licensed under the MIT license. Please see LICENSE for more information.
 *
 */

(function() {

// Create global ionic obj and its namespaces
// build processes may have already created an ionic obj
window.ionic = window.ionic || {};
window.ionic.views = {};
window.ionic.version = '1.3.1';

I would suggest you to re-write from scratch

I had a feeling that would be the best path forward. Thank you!