For countries that have undergone partition, the PPD estimates for a given year include all of the origin country’s then-current territories. This means that for dates before partition, all of the once united territory is included: estimates for Sudan before 2011, for example, include present-day South Sudan.
Where survey data are available from before the breakup for the territory of successor states, these data have been used to generate PPD estimates like anything else in the source data (the DCPO routine does not make any effort to incorporate information from the origin state into estimates for the successor state).