Microsoft is encouraging users to adopt the new Outlook app, which has been the default email and calendar solution for Windows 11 since its launch. Users face challenges with the new Outlook, including advertisements unless they pay for a subscription and the absence of several features from the previous Mail & Calendar app. Many users still prefer the classic Mail & Calendar app and express a desire for its return. The new Outlook is categorized as a Progressive Web App (PWA), raising questions about its classification as a native application. Critics have pointed out issues with the app's performance, design, and feature set, with some stating it does not meet user expectations. Microsoft has disabled the Mail & Calendar app on Windows 10 to compel users to transition to the new Outlook.