In Odoo 15, the backend URL structure has changed, so the hashchange event is no longer triggered when navigating between pages. This is because the URL now uses a route system rather than hashes to indicate the current page.

To detect changes in the current route, you can use the odoo.__DEBUG__.services['web_tour.tour'].router.current_route variable in your JavaScript code. You can listen for changes to this variable and perform any necessary actions when it is updated.

Alternatively, you can use the web_tour.tour service to listen for route changes and trigger your custom code. Here is an example:

odoo.define('my_module.route_listener', function (require) {
'use strict';

var Tour = require('web_tour.tour');

Tour.register({
id: 'my_route_listener',
name: 'My route listener',
path: '/web', // or any other route you want to listen to
mode: 'test',
onChange: function (page, next) {
// your custom code here
// `page` is the current route
next();
},
});
});