Mac users interested in Telegram macosx 10.5.8 generally download:
Messenger for Telegram is a messenger app based on the MTProto protocol. Telegram is a messaging app with a focus on speed. It’s fast, simple and free. With Telegram, you can create group chats with up to 200 people so you can stay connected with everyone at once.
Telegram is a desktop messenger that uses the services with the same name. The program has a nice minimalistic interface which nobody should have problems to use. In fact, it looks quite similar to the mobile app, and even its window has the shape of a smartphone. It has four main tabs: contacts, phone calls, chat and settings.