Not long ago WhatsApp published a new version of your app for Windows, based on the application platform universal. After its launch, it has been receiving updates correcting errors and polishing the application. In this update they have not only limited themselves to continue correcting bugs, but they also update a fundamental part of their design.
WhatsApp (Beta) adopts the WinUI 2.7 design in its latest update
It is no surprise that this application can be family to the one we had on Windows Phone, especially looking at some sections. And it really is so: this application is a port of the Windows Phone version, based on Silverlight. We do not know if the port is recent, or instead it was a adaptation to Windows 10 Mobile that was left in the I forget after the abandonment of the system by Microsoft.
This explains reasonably that the WhatsApp application is so light in terms of memory consumption due to the limited memory that the Lumia had, but that has a very outdated and some problems of performance caused by the implementation of Acrylic.
But in the latter upgrade WhatsApp for Windows with version number 2.2201.2.0 have made a change in their design: they adopt WinUI 2.7, which results in part of the context menus Y dialog boxes conform to the design lines of Windows 11.