Franz

One messenger to rule them all.  Meet Franz

"Franz is a free messaging app / former Emperor of Austria and combines chat & messaging services into one application. Franz currently supports Slack, WhatsApp, WeChat, HipChat, Facebook Messenger, Telegram, Google Hangouts, GroupMe, Skype and many more. "

Now your Windows can just run Franz, and you can chat to multiple folks using various different chat engines or messengers. Great!