Symptoms
Assume that you create a Microsoft Skype for Business 2016 meeting that has the Disable IM option enabled in the Meeting Option settings in Microsoft Outlook. Then, you clear the Disable IM option to enable IM for the meeting. When you join the meeting, you find that IM is still disabled.
Resolution
To fix this issue, install the October 10, 2017, security update for Skype for Business 2016 (KB4011159).
