Symptoms
In a Korean Input Method Editors (IME) environment in Microsoft Skype for Business 2016, assume that user A starts an instant messaging (IM) session with user B. After the users finish the conversation, user A can change the original conversation content by toggling the language to Hangul in the conversation display window and then typing some Korean text. It's expected that users should not be able to type anything in the conversation display window in this scenario.
Resolution
To fix this issue, install the October 2, 2018, update (KB4092445) for Skype for Business 2016.
