My browser said that too, but that certificate may be cached from a while ago. The terminal gives a different set of dates: $ openssl s_client -servername tw

My browser said that too, but that certificate may be cached from a while ago. The terminal gives a different set of dates: $ openssl s_client -servername twitter.com -connect twitter.com:443 2>/dev/null | openssl x509 -noout -dates notBefore=Nov 14 00:00:00 2022 GMT notAfter=Nov 14 23:59:59 2023 GMT Edit: Opening my browser in incognito now shows the new expiry too. The non-incognito version continues to show the old expiry.