Tier 4 - length to continue on student visa

[detheh]

Hello,
I am checking on behalf of my daughter .She is studying here from 2015(completed A levels). She was on Tier 2 -dependent visa & then switched to Tier 4 student Visa in 2017 to pursue degree course, currently in last year of 3 year degree course and planning to do post grad so will be completing university in 2021.
I would like know for how long she can continue on Tier 4 student Visa.
By 2021 ,she will complete 4 yrs on student visa .can she enroll for further studies and apply for Tier 4 student visa for another 2 years?
Or for how many years she would be eligible to extend and continue on Tier 4 student visa on any valid university course
Thank you for all your help!
Kind Regards.

[CR001]

Your previous posts suggest you and your dependents are/were on ICT Dependent visas looking to switch to tier 4 dependent??

uk-tier-4-student-visas/ict-tier-2-to-t ... l#p1772058