On the official Arquillian site I found table with supported container adapters https://docs.jboss.org/author/display/ARQ/Container+adapters. There is only one Java EE 7 container and it is in category "Container adapters managed outside of the Arquillian project". I conclude that Arquillian doesn't support Java EE 7 (yet?). But there are presentations https://www.parleys.com/talk/testing-java-ee-applications-arquillian about testing Java EE 7. Arquillian is used. I found sources https://github.com/javaee-samples/javaee7-samples and Glassfish 3.1 is used.
So does Arquillian support Java EE 7? Why peopele use old Glassfish (Java EE 6) while testing Java EE 7?