I recommend Franz (<a href="http:&#x2F;&#x2F;meetfranz.com&#x2F;" rel="nofollow">http:&#x2F;&#x2F;meetfranz.com&#x2F;</a>). Does Whatsapp, works on Linux, mac, pc. Supports Slack, WeChat, HipChat, Facebook Messenger, Telegram, Google Hangouts, GroupMe and Skype.