Effective on December 1, 2017, all newly issued Symantec SSL certificates (including GeoTrust, RapidSSL, Thawte, and Symantec) will now use a new Digicert signed intermediate certificate. Digicert recently acquired the certificate business from Symantec.
Symantec was penalized by Google due to security issues with regards to properly vetting SSL certificates in the past. Google Chrome issued a plan to phase out trust in Symantec certificates over the next 18 months.
As part of this transition, newly issued Symantec certificates will be signed with Digicert’s root certificate in order to continue to be trusted by Google Chrome and other major browsers.
New intermediate certificates can be be found at the links below: