When a critical security issue is discovered in the software, it would be great to get more info on which versions of MachForm it affects. So if a security issue is discovered... we really should be made aware of which versions of the software the issue affects so we can make an educated decision on whether to update or not.
Honestly it seems a bit counterintuitive to not provide critical fixes (patches) even for older versions that are no longer within the 'free update' period as most software companies provide. Releases of the software with new features could require a customer to pay the upgrade fee but a security patch isn't really an upgrade but rather a fix for an existing issue in the software previously licensed.
Imagine if Microsoft charged people for security fixes... our bank accounts would be drained dry to keep our systems secure. Just my two cents...