It appears something Google allowed to happen in 2008 has happened again: # openssl s_client -starttls smtp -connect smtp.gmail.com:587 CONNECTED(00000003) depth=3 C = US, O = Equifax, OU = Equifax Secure Certificate Authority verify return:1 depth=2 C = US, O = GeoTrust Inc., CN = GeoTrust Global CA verify return:1 depth=1 C = US, O = Google Inc, CN = Google Internet Authority G2 verify error:num=10:certificate has expired notAfter=Apr 4 15:15:55 2015 GMT
Just an FYI in case anyone has end users start reporting errors sending email.