Hi [mention:3bc29179d822403aaf13b45b8085d735:e9ed411860ed4f2ba0265705b8793d05],
You can find the What's New of Central admin here: https://docs.sophos.com/central/Readmes/en-us/scloud_readme.html
At present time, we do not have any PhishThreat release notes.
Hope that helps