It's not about "valid" or "no more valid". It's about context.

If you want to distrust a security vendor for greenlighting something that was found to be vulnerable the following week, you'd probably be in the clear.

If it was 6 years ago? Maybe don't count that against them; especially if it's a novel vulnerability that was discovered.

But also, if you're running 6 year old software, maybe update to a newer version of it.