[stunnel-users] Possible to verify client certificate BUT ignore expiration-date?

All, Does anyone know if it is possible to perform all other verification of a client certificate EXCEPT allow the certificate to have expired? We have a vendor whose certificate has expired, and we want to allow their old certificate to work while they chase their tails trying to figure out the best way to re-issue a new cert for us. *eyeroll* Is it possible? Thanks, -chris