List of available trusted root certificates in iOS 11

The iOS 11 Trust Store contains three categories of certificates:

Trusted root certificates are used to establish a chain of trust that's used to verify other certificates signed by the trusted roots, for example to establish a secure connection to a web server. When IT administrators create Configuration Profiles for iPhone, iPad, or iPod touch, they don't need to include these trusted root certificates.
Always Ask certificates are untrusted but not blocked. When one of these certificates is used, you'll be prompted to choose whether or not to trust it.
Blocked certificates are believed to be compromised and will never be trusted.

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在iOS 7.1版本之后，通过itms-service安装应用时，要求itms-service协议后面的url的值即plist文件的地址必须为https地址，且设备必须信任此https服务器的SSL证书。

If your users are on iOS 10.3, they will need to follow the following steps to trust a certificate included in a profile

Ensure they have installed the profile on their device.
Open Settings.
Navigate to General and then About.
Select Certificate Trust Settings.
Each root that has been installed via a profile will be listed below the heading Enable Full Trust For Root Certificates. Users can toggle on/off trust for each root.