WhatsApp is finally rolling out multi-account support on iPhone, bringing one of its most requested features to iOS. Here are the details. Add new or existing accounts Last November, WhatsApp began testing multi-account support with beta users on iPhone, bringing one of its longest-requested features a step closer to launch. The beta rollout came months after WABetaInfo spotted references to the feature in the app’s code, alongside groundwork for the upcoming username system. While username support is still in development, WhatsApp is now officially rolling out multi-account support to users via the App Store version of the app. As WABetaInfo noted , WhatsApp officially announced the feature a few months ago, but “not all users were able to add a second account immediately,” as it was “still available only to a limited number of users.” That’s hardly unusual for WhatsApp, which is known for its slow, phased rollouts.…