1. The specialized app for i1

A:  The message will pop up automatically to ask whether to install the FiiO Controller app, when the i1 first time connects with the Apple device. FiiOController app which is delicated for i1, is just mainly used to upgrade the firmware for i1. You can select to download and install it according to that message, or search it later from App Store.

When you open FiiOController app first time, there will be the Language option setting, including simplified Chinese, tranditional Chinese and English. 
1. If you carelessly selected the wrong language, please try to connect the i1 with the Apple device firstly, then click "Guide"(操作指导) in the bottom right corner, and click the icon "A" in the top right corner on the Guide interface. Then, you can change to select the language which you want. 

2. Please check the following picture to know how to upgrade the i1. At present, the latest firmware version for the i1 is 1.2.2.