The thing is, grade boundaries will automatically be adjusted, because each year a statistical formula is applied so that a very similar proportion of students get each grade to previous years, with some adjustment for known prior attainment of that cohort.
So say in a normal year, 76% is the A/B borderline. Next year it might be 72%, or 68%.
That adjustment doesn't need ANY changes to be made to papers or procedures - it's a statistical post-marking analysis.
A more dramatic option might be to widen the choice of, or limit the number of, topics for which questions need to be answered, to take account of material that might not have been covered.
So paper might have 'choose 2 out of the following 3 questions', whereas previously there might have been 1 question on each of 2 topics with no choice.
However, i don't think that is likely, simply because the length of gestation time for exam papers is so long!