Microsoft will be shutting down its Cortana app on Android and iOS as of January 31 next year, at least for certain markets. That's indicated by posts in the support forums in the UK, Canada, and Australia websites, which sounds like a global development, though there's no such word for the US. As the post clarifies, the content you've created within the app will continue to be accessible through Cortana on Windows, but in the app itself or the Microsoft Launcher. Additionally, the Microsoft To Do app will let you access reminders lists and tasks, which are automatically synced....
Source: https://www.gsmarena.com/microsofts_cortana_app_android_ios_no_more_january_31-news-40139.php
