migrate_ci_to_ce doc is not totally clear

I have several questions about this doc: http://doc.gitlab.com/ce/migrate_ci_to_ce/README.html :

• If I currently run a 7.14 omnibus package with both CE and CI on the same server, should I care for migrations?
• This sentence is not clear: You can only migrate CI data from GitLab CI 8.0 to GitLab 8.0. What if I am in 7.14 and want to go to 8.0?
• In II.1., On Omnibus GitLab servers you will have to add a line to /etc/gitlab/gitlab.rb, what line should I add? Something like gitlab_ci['XXX'] = but which XXX?

Thanks by advance for your help ;)