Adding Historic Years

Hi, we've been asked to update our application so that data can be loaded for more historic years. At the moment the starting year is 2018 but now we want to investigate the possibility of adding years 2014-2017. The options we have is to rebuild the application with 2014 as the starting year or alternatively (because the historic data is just for the full year from 2014-2017) we could load the annual data into custom periods (FY14, FY15, FY16, FY17). I understand that this may cause some confusion when reporting data (as we will have to load the custom periods