Jon
How long do we need to support NEW users that have antique OS?
Poor me
. My Calibre (and Sigil) evolved to where it (the current feature set) would not run on my old Athelon CPU (did not matter if Linux or XP. The chip no longer provided support for the modules needed for these apps).
Old users (of Calibre) have warning to
backup their config folder (where the installed Plugins are), in case they need to restore.
There will not be changes or features added to these OLD versions, so leave the burden on the few that are stuck on these minimal systems.
Switching to Linux, may allow these under powered/ limited RAM systems to continue to be used for a while, but at some point, parts are going to fail and they need to move on. Folk with limited resources, should check with their local community, there may be donated/replacement hardware (and folk to help transition files) for little or no cost.