The mystery of the expiring Sectigo web certificate


There’s a bit of a kerfuffle in the web hosting community just at the moment over an expired web security certificate from a certificate authority called Sectigo, formerly Comodo Certificate Authority.

Expired certificates are a problem because they cause the web server that relies on them to show up as “invalid” to any program that tries to do the right thing and verify the validity of the site it’s connecting to.

But this problem isn’t Sectigo’s fault – indeed, the company has had a warning about the impending problem available for a while now, explaining what was about to happen and why.

The problem comes from what’s known as backwards compatibility, which is a jargon way of saying “trying to support old software reliably even though it really ought to have been upgraded to a newer and more reliable version”.

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