Microsoft had actually confirmed last year that it w ould release a dark mode for Outlook on both iOS and Android but it didn’t say precisely when it would do that. Microsoft previously said that it was working on a dark mode for OneNote and it’s now doing the same for Outlook.
Not only does a dark theme look really nice but it also helps reduce battery usage on devices with AMOLED displays.
Having a dark mode for your app is in vogue these days so it’s hardly surprising to hear that Microsoft is working on one for Outlook as well.