several carrier-specific features may not be available for your apple 6 what does this mean

[tflybird]

IPhone questions about service carriers if refurbished cell phone is unlocked

 

[hang-the-9]

It means that if something is available from a carrier only, it will not be on every single iPhone. Carriers sell phones with their own programs and features installed. If you use a unlocked phone on another carrier, those things will not be on your phone even if you switch carriers.