New version supports iOS 11, which will not support 32 bit apps anymore. Apple started releasing iOS 11 on new iPad Pros so we started getting questions / complaints about the compatibility issues.
With the change, we also had to change the code to use Auto Layout. Since Korean Letters 1.0.8, there were many iOS devices released by Apple, with various screen resolutions. To support all of them, the app needs to use Auto Layout, which makes it somewhat like Android app development. There is no content change, but you will find some differences because of this.