I want to decrease a few options I have given out as free in one of my app (Universal iOS app) but I do not want any current users to update and lose those options.
Is there any way I can update my app without offering it to the current users. Only new users get the new app?
No it's not possible. Update is always available for all users that purchased the app.
You may think about adding in-app for those feature and make those in-app already available for the application already installed. The problem is that if the user deleted the application from the phone and install it again, you have no way to know he purchased a previous version (except if you have user login inside the application).