Early voting data:
Until the moment, 2,726,338 voters cast an early ballot. The number could still increase. Here's the early votes numbers by district and compared with 2014:
We can see from these numbers that early voting is up strongly where SD has traditionally had the most support, particularily in Skåne, while surprisingly it has substantially decreased in the regions where SD has had almost no support at all, mainly in the north of Sweden. This should be a huge worrying and warning sign for everyone who doesn't want SD to have a huge election night. If election day voting will look even remotely like this, I think it's almost a foregone conclusion that SD will become the largest party. However that is a big if of course.
It’s bit of a mixed bag but these figures seem broadly in line with what you might expect from the changes in party support since 2014 based on the polls. S areas generally taking the biggest hit, M a bit of both, and SD areas generally over performing. I think it really depends how many of those new voters in some more M leaning counties are voting SD.