经历了近两个小时的“狂欢”后，苹果逐步关闭了所有的老iPhone降级通道，尽管苹果通常时隔几年便会不经意间开放一次降级验证，但本次规模之大实属罕见。系统版本碎片化低一直是苹果iOS引以为豪的亮点，这样能为开发者降低适配难度，但升级新系统之后部分网友也反馈老iPhone存在卡顿、体验不流畅...
After nearly two hours after the "carnival", apple gradually closed all old iPhone down channel, although apple is usually after a few years will inadvertently open a demotion, but the scale is rare. Low system version fragmentation has been the glory of apple's iOS, so can reduce the difficulty of adaptation for the developers, but after the upgrade new system exist some netizens also feedback old iPhone caton, the experience is not smooth...
