My project must support iOS6.
I use Google Sign-In SDK v2.4.0. But When I selected Target , the GoogleSignIn.framework (optional) in Xcode project and run on the iOS6 device, dyld log tells
dyld: Symbol not found: _OBJC_CLASS_$_NSURLSessionConfiguration.
Is there how to use this in iOS6 Device??
The GoogleSignIn guides don't state a minimum SDK version however...
NSURLSessionConfiguration was introduced in iOS7 so if you are getting that issue when trying to link to the SDK then iOS 6 certainly isn't supported.
Checking out the sample project (pod try Google) and it also has the Deployment target set to iOS 7.0 so it looks like you are out of luck I am afraid. Maybe look at using an older version but I can't help you with what version supports iOS 6 and I would not know if it is still supported/maintained by Google.