The Apple Push Notification (APNS) certificate for HCL Sametime Proxy 11.6 expires on April 8, 2022. HCL Sametime Proxy 11.6 IF2 updates the APNS certificate. It is valid until June 3, 2023.
How to upgrade HCL Sametime 11.x LINK or LINK
After installing IF2, check the settings according to this article LINK