Added credit card not showing up
Looks like the issue was unrelated to the version of CRM I was running. The payment processor settings also needed to be edited to include Discover, after adding it to the list of accepted credit cards; Administer > CiviContribute > Payment Processors. After I cleared everything in the sites/default/files/civicrm/templates_c directory, I was able to see the settings to turn it on. Oop!