The new hangout interface removed apps and extension support.

The new hangout interface removed apps and extension support. Old users can still access it. But new users are always presented with new hangout interface even in HOA.
Does anyone know of any method with which new users can also access old hangout interface that had apps and extension ?

In the below pic you can see that it opens the extension preloaded by appending "&gid=app_id" in the url. But there is no way user open it again once he opens any other app. because its shortcut is not available in left hand side menu.