The Galaxy S5 Mini has yet to be announced, however it still received a quick mention in today's update of NNL Fingerprint Passport in the Samsung Apps store. As noted within the "What's new", the app Added support for screen rotation and S5 mini.
Of course this still doesn't make the S5 Mini official, though as we saw back in April, it could very well be on its way. The S5 Mini rumored to be packing a 4.5-inch 720p SuperAMOLED display, 1.5GB of RAM, an 8MP rear and 2MP front cameras and a 2100 mAh battery.
Last check pointed to a "likely" June launch, so we could see the S5 Mini in just a few weeks.