Link is broken https://www.dropbox.com/developers/core/docs#longpoll-delta , can anyone working link
That link was for Dropbox API v1, which has been retired. You should use Dropbox API v2 now. You can find everything you need to get started with Dropbox API v2 here.
For reference, the API v2 equivalent of that API v1 "longpoll-delta" endpoint is /2/files/list_folder/longpoll.
