You are looking for end-of-life and product lifecycle information for Edge Secure Web Gateway (ProxySG) or Advanced Secure Gateway (ASG) devices and software.
See the PDF under Attachments, which identifies key dates for platforms and software that have reached end-of-maintenance or end-of-life in their product lifecycle (these are listed by model/version number).
For a complete list, see End of life and product lifecycle information for Broadcom, CA, and Symantec products.