Starting with version 0.13 , SAML Single Sign On for JIRA allows authenticating users on the JIRA 7 Service Desk Customer portal (https://<jira>/Servicedesk/Customer/portal).

Existing users can be authenticated (and updated) and new users can be created on the fly during login (see Create or update users with data from a SAML response).

Before version 0.14.3, no groups were assigned to SD Customer-users. Starting with 0.14.3, users are assigned to the groups included in the SAML-Response from the IdP. They are not  assigned to the groups specified in the Groups parameter in the IdP settings. This allows to add regular users to groups like jira-software-users by default (what causes a license to be consumed).