Vulnerabilities are going to come up, absolutely. Unless you believe that the older version is somehow 100% bug free and vulnerability free just by virtue of it

Vulnerabilities are going to come up, absolutely. Unless you believe that the older version is somehow 100% bug free and vulnerability free just by virtue of it being old. Being old doesn’t grant it any magic powers. What’s old now is what was bleeding edge years ago - it hasn’t been updated (otherwise it wouldn’t be old), it has just gotten older. And the problem with keeping old versions around is that when (not if) someone does discover a vulnerability, what are you going to do then? If your answer is “we’ll patch it then”, then that’s not going to be an old version anymore, is it? If your answer is “I guarantee it will 100% never have any vulnerabilities ever and so it will never need to be updated”, I don’t think we’re living in the same reality.