Why the Apocrypha/Deuterocannon?
This would inevitably seem controversial, and there was a measure of struggle in deciding whether to include or exclude this. But the decision in the end was made to include it because it is afterall, part of the original text of this specific version that is being used. An alternative copy of the KJV without the Apocrypha/Deuterocannon is also provided, for those who wish to use that instead.
Why the KJV only?
This is mostly for copyright reasons. Currently this is the only version that was easily accessible without the need to deal with copyrighting issues, the only precondition to its use being the exclusion of the United Kingdom from the distribution list.
Perhaps some time in the future, an opportunity might present itself for the inclusion of other versions.
Why is this application not available in China?
Chinese law requires some kind of legal shebangs to be fulfilled, including the acquisition of some kind of license, if a religiously-related application seeks to be published in the the AppStore in China. As you can probably tell from my unspecificity, I have not yet figured out what these requirements are, so the exclusion of China from the distribution list makes the most sense at present.
Perhaps this might change in the future, if the opportunity presents itself.