https://thenextweb.com/apps/2020/03/03/its-official-whatsapp-is-rolling-out-dark-mode-to-all-users/

WhatsApp is finally launching its most requested feature: Dark mode. The stealthy option has basically become a must-have feature for apps over the past year or two, and though a select few Android users have seen previews of the feature show up, this is the first time the company is officially supporting it for all Android and iOS devices.

WhatsApp notes that its primary focus was reducing eye-strain in low light environments.  That’s why, unlike some other apps, the dark areas aren’t quite pitch black. During testing, the company found the contrast of pure black and white can lead to eye fatigue, so it’s using a dark grey background instead. It also used colors and other design elements “to make sure the most important information stands out.”