The desktop app will prompt you to upgrade when there's a major update. Minor updates are released frequently but you won't be notified by default.
If you want to be notified when any HipChat update is available:
- Click on the gear icon in the desktop app to access settings
- Check the box next to "Notify me of all HipChat updates"
- Click Save
From the top level menu, choose "HipChat -> Check For Updates..."
On Windows and Linux
Right click on the system tray icon and choose "Check For Updates" from the popup menu.
If an update is available, you will be shown the update window. Just click "Install update" and the app will handle it from there.
If your client is fully update to date, a small popup will show indicating your current version.
PS: If you prefer to use shortcut keys, you can also press ctrl+shift+U to check for updates without using any menus.