To use the persistent chat APIs, the following prerequisites must be met:

• The persistent chat feature must be enabled in Skype for Business. Refer to your Skype for Business documentation for instructions.
• Users must be enabled for persistent chat on BEMS. For instructions, see the BlackBerry Connect Administration content.
• UCMA SDK version 4.0 or later must be installed on the computer hosting the BEMS-Connect service to correspond to connections to Skype for Business.
• X-GC-VERSION http header value is set to 2.5.0.0 or later in the API calls. This is the minimum client version where persistent chat related features are enabled on the Connect service.