PhD students are entitled to a modest salary raise when they reach 25%, 50% and 75% of their PhD work (corresponding to 60, 120 and 180 credits). 

Your supervisors should report your progress twice a year to the PhD administrator, and when (s)he notices that you have reached the respective level, it is further processed so that you receive the salary raise.

The level reported by the supervisors should be verifiable by what is found in the ISP (i.e. the total credit for completed courses and completed elements of PhD works).

If you reach the threshold level in between the summer and winter ISP and wish to receive the salary raise, you need to take initiatives in bringing that up to the PhD administrator.