Sophos Endpoint on Catalina - Alternatives

Question

We've got a number of Macs that are no longer supported by Apple, (Catalina / 10.15.6) but we still want to retain for lab use / isolated. 
 
 I understand that the Sophos Endpoint / AV client for Catalina similarly went EOL in October 2022, but we'd still like to protect these devices with AV in one form or another. 
 
 However, we were able to still install Endpoint onto similar Catalina Macs as recently as a couple of months ago, but whenever we try now it simply fails to install - it will get as far as verifying the download. 
 
 With the above in mind, that the AV is unsupported, is anyone aware of a known issue to this? Sophos Endpoint / AV has historically been a bit of a nightmare to get running on macOS - this same scenario has happened before, and redownloading, or simply trying later, seems to resolve the issue. 
 
 The install.log file when viewed in console gives very sparse information.

GlennSen · Answer

Thank you for reaching the community forum.

From what I can see, the installation package no longer works on this later version of Mac OS, as this support has been retired. Like Windows servers already retired, you won't be able to install the package unless you have the required subscription for extended support. However, For MAC OS there’s no extended support available. You may refer to this KBArticle for the prerequisite.
However, this article may help you achieve this by installing the latest OS on an unsupported Mac device. You can install and manage the Sophos endpoint to those devices through your Sophos Central Dashboard.