Official app for OS X from Telegram team
This software is available under GPL v3 license.
Source code is available on GitHub.

Version history

v 0.9.46 alpha 27.04.16

  • Alpha versions instead of dev
  • Bug fixes and other minor improvements

v 0.9.45 dev 22.04.16

  • Bug fixes and other minor improvements

v 0.9.44 stable 20.04.16

  • Bug fixes and other minor improvements

v 0.9.43 dev 14.04.16

  • Select and copy text in photo / video captions and web page previews
  • Media player shortcuts are enabled only when player is opened

v 0.9.42 stable 12.04.16

  • Bug fixes and other minor improvements

v 0.9.41 stable 11.04.16

  • Introducing Bot API 2.0, the biggest update to our bot platform since June 2015
  • Bots can now update existing messages on the fly as you interact with them
  • New Inline keyboards with callback, ‘open URL’ or ‘switch to inline mode’ buttons help create seamless interfaces
  • Inline bots can now send all attachments supported by Telegram (videos, music, stickers, locations, etc.)

v 0.9.40 stable 05.04.16

  • Visual improvements

v 0.9.39 dev 01.04.16

v 0.9.38 dev 01.04.16

v 0.9.37 dev 31.03.16

v 0.9.36 dev 26.03.16

  • Bug fixes and other minor improvements

v 0.9.35 dev 25.03.16

  • Design improvements

v 0.9.34 dev 17.03.16

  • Bug fixes and other minor improvements

v 0.9.33 stable 16.03.16

  • Linux version critical bug fixed

v 0.9.32 stable 14.03.16

  • Bug fixes and other minor improvements

v 0.9.31 stable 14.03.16

  • Supergroups can now have 5,000 members (up from 1,000)
  • Groups of any size may be converted to supergroups
  • Make your supergroup public by setting up a public link – anyone will be able to view the chat and join it
  • Pin messages to keep important updates visible and notify all members
  • Select messages to delete, report as spam, block users, or remove all messages from a user

v 0.9.30 dev 03.03.16

  • Bug fixes and other minor improvements

v 0.9.29 dev 01.03.16

  • Ctrl+W or Ctrl+F4 for close window (Cmd in OS X)
  • Ctrl+L to lock Telegram if you use a local passcode (Cmd in OS X)

v 0.9.28 stable 26.02.16

v 0.9.27 dev 25.02.16

  • Edit your messages in channels and supergroups
  • Share links to specific posts in channels via the post context menu
  • Add admin signatures to messages in channels
  • Send silent messages in channels that will not notify members, useful for non-urgent or late night posting

v 0.9.26 stable 22.02.16

v 0.9.25 dev 21.02.16

  • Adaptive layout for wide screens switch added to Settings
  • Linux version crash fix

v 0.9.24 stable 16.02.16

  • New waveform visualizations for voice messages
  • Sticker suggestions when you type an emoji

v 0.9.23 dev 15.02.16

  • Bug fixes and other minor improvements

v 0.9.22 dev 14.02.16

  • Voice messages waveform visualizations

v 0.9.21 dev 09.02.16

  • Bug fixes and other minor improvements

v 0.9.20 dev 08.02.16

  • Testing new crash reporting system
  • Conversation history is centered in wide windows
  • New cute link and timestamp tooltips design
  • Ctrl+W or Ctrl+F4 closes Telegram window

v 0.9.19 dev 09.01.16

  • Choose an emoticon and see the suggested stickers

v 0.9.18 stable 05.01.16

  • Bug fixes and minor improvements

v 0.9.17 stable 04.01.16

  • Crash fixed

v 0.9.16 stable 04.01.16

  • GIFs autoplay and automatic download
  • Inline bots support
  • Automatic download settings added
  • All media redesigned

v 0.9.15 stable 09.12.15

v 0.9.14 dev 09.12.15

  • Sticker management: manually rearrange your sticker packs, pack order is now synced across all your devices
  • Click and hold on a sticker to preview it before sending
  • New context menu for chats in chats list
  • Support for all existing emoji

v 0.9.13 stable 25.11.15

  • Groups can now have multiple administrators with the ability to edit the name and logo, and add and remove members
  • Groups that have reached their capacity of 200 users can be upgraded to supergroups of up to 1,000 members

v 0.9.12 dev 22.11.15

  • Bug fixes and other minor improvements

v 0.9.11 dev 22.11.15

  • Groups can now have multiple administrators with the ability to edit the name and logo, and add and remove members
  • Groups that have reached their capacity of 200 users can be upgraded to supergroups of up to 1,000 members

v 0.9.10 stable 04.11.15

  • New shared audio files section
  • New design for popup menus
  • Add captions to any photos you send
  • Surround text with `single backticks` for inline monowidth code and ```triple backticks``` for blocks of code
  • The Tilde symbol is now displayed correctly

Alpha version

If you would like to get all updates faster and be the first to test new features, you are welcome to use Telegram Desktop's alpha version instead of the stable one.

The stable version is updated less frequently, but is tested better than the alpha version.

Here are the alpha version links for different platforms:

Windows Setup
Windows Portable
Mac OS X 10.8+ Setup
Mac OS X 10.6 and 10.7 Setup
Linux 64 bit
Linux 32 bit

Just install it on top of your current Telegram Desktop and there you go.
Your feedback is welcome on Twitter