Upgrade ArcGIS JavaScript API Web App

My production-grade web application currently mixes ArcGIS JavaScript API 3.x and 4.x code. I want the entire front-end moved to the latest 5.x release so I can take advantage of its modern framework, performance improvements and long-term support. Core workflows to preserve • Geospatial data management remains the heart of the app. • Users must still add, remove and reorder layers, change symbology and toggle visibility exactly as they do today. • Interactive maps with pop-ups have to remain responsive and accurate. • Custom widgets and tools (including a bespoke polygon editor that lets users query, create and edit vector features) must be rebuilt or refactored so behaviour is unchanged. Upgrade goals Beyond parity, I’d like the user interface refreshed to feel lighter and more intuitive. If the new version offers UI components that can replace my hand-rolled elements, please recommend them. Deliverables 1. Fully upgraded codebase running on ArcGIS JavaScript API 5.x. 2. Migration notes outlining replaced/deprecated classes, new patterns adopted and any remaining 3.x/4.x calls (should be none). 3. Refactored custom widgets, pop-ups and polygon editing tool, tested in the latest versions of Chrome, Edge and Firefox. 4. A brief hand-off session (recorded or live) walking through the new build process and deployment steps. Acceptance criteria • All existing map interactions and editing functions work as in production. • No console errors or deprecation warnings related to 3.x/4.x code. • UI improvements implemented without breaking familiar workflows. I will provide the current code repository, sample data and a staging server for testing. If you have recent experience migrating large ArcGIS apps and can demonstrate it, I’m ready to get started. The ArcGIS Rest API in not reachable to the internet. Please use your own ArcGIS Rest API for testing. Alternatively we can use VPN but need to request time by time for us to standby and provide the token. App version: - PHP 8.5 - Laravel 13 - Vue.js - SQL Server Total page affected is around 80 pages (blade file). Project timeline: 50% by 15th October 2026 100% by 5th November 2026