During the WWDC 2015 Platforms State of the Union presentation, they mentioned that iOS 9 requires TLS 1.2 SSL for all hosts unless you specify domains that you'd like to make exceptions for in your app's Info.plist file.

AVOSCloud iOS framework doesn't seems to conform to TLS 1.2, I have to disable the security for all network communication in the project's Plist file :

<key>NSAppTransportSecurity</key>
<dict>
    <key>NSAllowsArbitraryLoads</key>
    <true/>
</dict>

v3.1.4 已经对 App Transport Security 进行全面支持了。