As a Student visa holder (formerly Tier 4 visa, prior to 5th October 2020), there are certain responsibilities that you have, and that the University has. For example, you must make sure that your information is up-to-date on the Student Self-Service, and inform the University any time you get an updated passport.
The Faculty must monitor your attendance and make sure that you are engaged with your studies. The easiest way for us to this is for you to complete a termly report on the Student Self Service reporting system. If we have not heard from you all term, you may be contacted by the Graduate Office, to check in and see what you have been up to. The University must report any unapproved absences to the Home Office, which can affect the status of your visa, so it's good to always keep us in the loop.
You can find further details about your obligations on the University page, here.
You can contact the Student Immigration Team by emailing student.immigration@admin.ox.ac.uk
The Home Office page about the Student visa is available here.