I'm currently looking for a shapefile for Pakistan with the current district borders. So far I found something on https://gadm.org/. Unfortunately the shapefile there seems not to be up-to-date, as e.g. one district has been split into two in 1996, but in the shapefile it's still one district (and in some other cases the names seem to be the old ones).
Is there any "general source" with newer shapefiles (also for other countries)?