來源：MacRumors https://goo.gl/1KDZV8
Source:iOS 11.4 Disables Lightning Connector After 7 Days, Limiting Law
Enforcement Access
(內文長，擷幾個重點)
The iOS 11.4 update, currently being beta tested, includes a USB Restricted
Mode that introduces a week-long expiration date on access to the Lightning
port on your iOS devices if your phone hasn't been unlocked, which has
implications for law enforcement tools like the GrayKey box.
新的iOS11.4目前正在進行Beta測試，其中一項功能包括「若一個禮拜沒有解鎖裝置，就會
上鎖Lightning孔」，這項功能應該是為了阻止GrayKey box等法律性質工具強制破解手機。
In Elcomsoft's experience, after an iPhone or iPad has been updated to iOS
11.4, if it hasn't been unlocked or connected to a paired computer in the last 7
days using a passcode, the Lightning port is useless for data access and
limited to charging.
根據人員測試，更新iOS11.4的iPhone和iPad若在7天之內沒有解鎖或連接配對的電腦，
Lightning孔就會失去資料傳輸功能而僅能充電。
USB Restricted Mode won't prevent tools like the GrayKey box from being used
on an iPhone, but it does suggest that the passcode needs to be discovered
within a matter of days, severely limiting the amount of time that law
enforcement officials have to get into a device.
USB限制模式無法阻止GrayKey box等工具破解手機，但確定的是時間內必須被迫解，這
對法律用工具有極大的影響。
USB Restricted Mode was actually first introduced in the iOS 11.3 beta, but
it didn't make it into the iOS 11.3 release, so its presence in the iOS 11.4
beta does not guarantee that it will be included when iOS 11.4 launches to
the public.
其實USB限制模式在11.3beta版本中便出現過，但沒有進入最後public版本，所以這項功能
在11.4 public版本並不保證會出現。