Since our current S/MIME certificate for our Mail-to-SMS API will expire soon, we have just renewed the certificate. You can find the new certificate here: https://app.sms77.io/certificates/smime/mail%40gateway.sms77.io.pem The current certificate will expire on 8 January 2024. If you are using our encrypted Mail-to-SMS API you should refresh the certificate in your system to avoid any outages.