Can't find AFHTTPClient on AFNetworking 2.0, to use:
AFHTTPClient *client = [AFHTTPClient clientWithBaseURL:[NSURL URLWithString:@"http://examplewebsite.com]];
[client setAuthorizationHeaderWithUsername:@"username" password:@"password"];
How it needs to be manage on AFNetworking 2.0?
AFNetworking 2.0 new architecture use serializers for creating requests and parsing responses. In order to set the authorization header, you should first initialize a request operation manager that replaces the AFHTTPClient, create a serializer and then call the dedicated method to set the header.
For example you code would become:
AFHTTPRequestOperationManager *manager = [[AFHTTPRequestOperationManager alloc] initWithBaseURL:[NSURL URLWithString:@"http://examplewebsite.com"]];
manager.requestSerializer = [AFHTTPRequestSerializer serializer];
[manager.requestSerializer setAuthorizationHeaderFieldWithUsername:@"userName" password:@"password"];
You should read the documentation and the migration guide to understand the new concepts that come with the version 2.0 of AFNetworking.