Student discount on international conferences for non-matriculated students In computer science many conferences provide a fee discount for PhD students.
Currently I am also a PhD student in Germany. In Germany there is a program in which you are registered as a PhD student at a university, but not matriculated. 

Can I still register for conferences via the student discount?
You're a PhD student, so, yes, you can register for the student discount.*

*Ultimately, conferences make their own rules, so this may not apply to every conference. In such cases, just ask the organisers.