They'll probably go up when compared to last year - if you look at when they changed the GCSE back in 2008 (I think it was this year) the grade boundaries were very low, and rose every year.
In 2017 with the new English/Maths GCSE the grade boundaries were low, and they rose for the 2018 cohort so I'd imagine they'd follow the same pattern and go up even more (unless the exam is incredibly hard - which is unlikely as the hardness is controlled relative to previous exams)