Update Xamarin app

We have a cross platform (iPhone and Android) app built in Xamarin. It was last compiled in 20016. Each version consists of a UI and a background task running on the phone and a common back-end server running on AWS. The app background task collects acceleration and GPS information, makes a decision and then communicates with the node/sails back end on AWS which in turn communicates with a sql database and sends e-mails, SMS messages and makes voice calls through Twilio. Users initially subscribe to the system through a WordPress site. Their phone app login is validated against the WordPress login credentials. Monetisation is through corporate sale of licenses. We need the following coding activity to update the system: Phase 1 – recompile and release update 1. For Android version 1.1. Update the app to use current libraries and meet current Google requirements for use of SDK 26 with Android 8 minimum OS version and Android 10 as target version 1.2. Replace Xamarin plugins with Xamarin extensions 1.3. Update/replace url libraries 1.4. Get code to compile in visual studio 2019 on pc 1.5. Regression test functionality through ad-hoc deployment with back end to ensure app works 1.6. Publish as an update to the current app on Google Play 2. For iPhone version 2.1. Update the app to use current libraries and target current iOS version 2.2. Replace Xamarin plugins with Xamarin extensions 2.3. Update/replace url libraries 2.4. Get to compile in visual studio 2019 on mac 2.5. Regression test functionality as ad-hoc deployment with back end to ensure app works 2.6. Publish as an update to the current app on App Store Phase 2 - in-app purchases and back-end update 3. Common Back-end server 3.1. Modify back-end to handle in-app purchases of subscriptions and corporate licenses (current model) 3.1.1. Properly document back-end rest api 3.2. Update back-end to modern version of node and sails 3.3. Move from grunt to pm2 for app management 3.4. Disconnect from WordPress for user signup and management 4. For Android version 4.1. Add complete sign-up capability to app (no dependence on WordPress sign-up first) 4.2. Add in-app purchases for subscriptions and corporate licenses 4.3. Publish as new app on Google Play 5. For iPhone version 5.1. Add complete sign-up capability to app (no dependence on WordPress sign-up first) 5.2. Add in-app purchases for subscriptions and corporate licenses 5.3. Publish as new app on App store Source code is on bitbucket. We require nightly commits to bitbucket. Skills required: linux, windows, mac, xamarin, app store, google play, bitbucket, visual studio, node.js, sails, aws, sql, xml, english Prefer Australian based developer. Please include references to published Xamarin based apps on google play and app store (must be the same app on both platforms) that you have been wholly responsible for. Your proposal will only be reviewed if there are references. Please propose an hourly rate.