An update with the build number G900TUVU1FOF6 has begun rolling out to S5 owners today, although the company has not yet officially announced the update or listed a change log for us to dissect.
However, we know from the previous S6 update that Android 5.1.1 includes new features such as Smart Lock factory reset, the option to remove toggles from the Notification panel, and a slight update to the Material Design elements in Samsung’s TouchWiz UI.
Samsung also introduced the Guest Mode from stock Android, a new Parallax Effect for wallpapers, and alphabetical app draw ordering with the Galaxy S6 update, so these features should hopefully carry over to the Galaxy S5 update as well. It is also likely that the new camera RAW file format and ISO adjustment options will be made available, at least when using third party camera apps.
The update is gradually rolling out over the air or can be grabbed as a manual download through Samsung’s Kies software. T-mobile seems to be ticking all of the right boxes with its fast update process.