I am on 6.4.3. It has full screen support in portrait. The problem is that in landscape there are huge blue bars at the top and bottom. And the actual viewing area is very small because of the bars. Portrait mode is not very good because it is not wide enough to display long lines. In order to improve usability on phones a full screen mode is needed. I am also using tesxtastic on an iPad and it is great there. Please add an option to hide the blue bars or have them hide automatically in landscape on an iPhone.