Despite having an edgy name that would make a goth punk rocker blush, Dark Mode basically replaces the app’s bright white background and colours with a… well, darker theme. This is to help users reduce eye strain when using WhatsApp in low light environments.
In order to further reduce eye fatigue, developers have specifically chosen colours that are closer to the system defaults on Android and iOS respectively. Additionally, in order to have important information to stand out, design elements on its interface have also been slightly tweaked. However, the Dark Mode feature has yet to arrive on both Android and iOS versions of WhatsApp in Malaysia. But when it does, you can activate it by accessing Settings > Chats > Theme, and select Dark. (Source: WhatsApp Blog.)
