     #endif
 
     #if os(iOS)
+    @available(iOS, introduced=8.0)
     private class func requestSharedWebCredential(domain domain: String?, account: String?, completion: (credentials: [[String: String]], error: NSError?) -> ()) {
         SecRequestSharedWebCredential(domain, account) { (credentials, error) -> () in
             var remoteError: NSError?

        case Always:
            return kSecAttrAccessibleAlways as String
        case WhenPasscodeSetThisDeviceOnly:
            if #available(OSX 10.10, *) {
                return kSecAttrAccessibleWhenPasscodeSetThisDeviceOnly as String
            } else {
                fatalError("Unavailable 'Touch ID integration' on OS X versions prior to 10.10.")

    public var rawValue: Int {
        switch self {
        case UserPresence:
            if #available(OSX 10.10, iOS 8.0, *) {
                return SecAccessControlCreateFlags.UserPresence.rawValue
            } else {
                fatalError("Unavailable 'Touch ID integration' on OS X versions prior to 10.10.")
