You can only go as far back as currently supported/in production devices as found here if privacy and security matter:
I explain a bit more in the following note.
Add to that using out of production devices is bad in that they no longer receive firmware/driver updates. This leaves you vulnerable to known patched vulnerabilities that could be exploited.
While there are always 0 days out there, these tend to be high value & used for similar targets (once used they are more likely to be noticed & patched). When vulnerabilities are disclosed post patch, lower level actors will start to use them increasing risk if not updated. This goes for apps too especially browsers.