4.10.1 BUG Metal required but not available?

I package my game for ios with metal like the screenshot below:but when I test it on my iphone 5s ios8.1.2,it pops up a warning like below and then crashes the game.Which shouldn’t happen on iphone5s.Thanks a lot!

74696-猎豹截图20160116105238.png

Metal is broken on 4.10.