With Windows apps being updated through the Microsoft Store almost independently from the major operating system updates, it's sometimes hard to pinpoint when and what new features have been implemented versus usual developer maintenance. Being a Windows Insider infinitely complicates feature tracking as some app updates become release triggered.
Now that I've applied a qualifying excuse to my overlooked reporting, I can say with moderate embarrassment, "hey guys, have you tried the new darker reading mode in the Windows 10 Mail app?"
I was tipped to its appearance via the Italian website Aggiornamenti Lumia where a gif was posted of the new toggle feature.
Mail UWP is getting more and more interesting. New useful toogle incoming 😎 https://t.co/yzFWRM59h1
— Aggiornamenti Lumia (@ALumia_Italia) January 17, 2019
Sure enough, the new toggle is available on my version of the Windows 10 Mail app running on the latest Fast Ring build 18317, despite there being little to no fanfare about it in the developer release notes. I'm not sure when it first appeared but users have been vocal about its implementation for over two years.
The dark preview pane may seem like a trivial addition, but its small details such as these that help bring cohesion to the platform and may help some users pivot from using Chrome or the big box version of Outlook, to the default mail experience in Windows 10. I know, I'm a fan of the app!
If you happen to know when exactly this toggled showed up, please feel free to drop that knowledge in the comment section for inquriing readers.