In the old version students or users could unenrol themselves from the courses by clicking on "unenrol me from this course" in the administration panel.
Ithat option is not there in the new version. So can someone tell me how can someone unenrol themselves, please ?
The existence of the "Unenrol me..." link is controlled by permissions now (1.7+). Here is a the Moodle Doc article on how to enable that button again.
http://docs.moodle.org/en/Unenrol
http://docs.moodle.org/en/Unenrol