Ionic emulate ios --target="iPhone-6s-Plus" says not a valid target

hi all, after I run "ionic emulate ios --target=“iPhone-6s-Plus”, there is error says:

Error: iPhone-6s-Plus is not a valid target for emulator

but ionic emulate ios --target=“iPhone-6-Plus” is fine.

also tried "ionic emulate ios --target=“iPhone-6s-Plus,.9.2”, but also says not a valid target for emulator

I am using “OS X EI Capitan”

any advices.

thanks

+1, I can not emulate iPhone-6s either. Does any one can help with this?