Set the group extension field

NSDictionary *changes = @{
    @"groupID": groupID,
    @"ex": mergedExtensionJSON
};

[[OIMManager manager] setGroupInfoDictionary:changes
    onSuccess:nil
    onFailure:nil];

ex is replaced as a complete string. The SDK does not merge JSON automatically. Parse the previous value before writing and preserve namespaces owned by other application modules.

The success callback, arrival of onGroupInfoChanged:, and a new query are three separate stages. For the complete delegate, see Groups overview.