Users have discovered that receiving a message with the characters "http://:", without the quotes, renders many of Skype's apps unusable, as they instantly crash. What's worse is that once that message is in your chat history, the apps will crash continuously upon restarting. So far it looks like the desktop version of Skype as well as iOS and Android clients are vulnerable to this bug, while the Modern Windows app and the Mac OS X clients are unaffected. Unfortunately there doesn't seem to be any easy fix to this. The only workaround seems to be quite convoluted, as the sender has to delete the message with the characters, and then the receiver needs to install an older version of Skype. However, it's not clear whether this actually works.