Microsoft has just pushed out an important update of Skype 7.13 For Skype. The improved version with support for Split View Mode improves multitasking during conversations.
According to the release blog post, Skype 7.13 for Mac also improves the contact list with an option to automatically add people you know in your Mac or other address books.
The update also fixes one bug provoking crashes of Skype. Microsoft reports that they are working on a fix to another bug where “Users may sometimes experience slow performance when switching to a conversation with large number of participants when running Skype on El Capitan.”
If you face any other issue with Skype for Mac, you can report to Microsoft from inside the App. Just go to Help > Provide Skype Feedback… using the menu.