In IPUMS Int'l, do the places of previous residence (e.g., MIGBR2) refer to consistent or inconsistent boundaries?

I am interested in identifying migrants’ places of residence according to the time-consistent boundaries. From what I have read it is not clear whether the codes for “place of residence 5 years ago” (e.g., MIGBR2) refer to the time-consitent or -inconsistent codes. Any clarification much appreciated.

For the Brazil “state of previous residence” variables, respondents are asked in which state they lived before their current state of residence (MIGBR1) or in which state they lived 5 years ago (MIGBR2). If the name of the state has changed, then they are instructed to use the state’s current name at the time of the Census. No further steps are taken by IPUMS to account for consistency of state boundaries over time for these variables.

Hope this helps.