This thread is full of FUD. China Unicom, the second largest mobile operator in the People's Republic of China supports LTE bands 3 and 41, both of which are supported on models A1778 and A1784 (the GSM models) of the iPhone 7.
If you're traveling to China just make sure you get a sim card from China Unicom and you should be ok regardless of what model iPhone 7 you have.
If you're traveling to China just make sure you get a sim card from China Unicom and you should be ok regardless of what model iPhone 7 you have.