Samsung has been updating its first-party apps with dark mode support ever since it released the feature in One UI a little over a year ago. In the last month or so, the company has quickly been updating the few apps left without one. The latest app to join the list is Samsung members, a one-stop-shop for deals on Galaxy products and accessories, news about software updates, support for your device, and joining beta programs when available.
With Samsung Members 3.5 installed, the app’s appearance will follow your system theme. The update is slowly rolling out through the Galaxy Store, but if you don’t want to wait you can grab it at APK Mirror now.
https://www.androidpolice.com/2020/02/24/samsung-members-gains-dark-mode/