Hi Michael, Looking at the data, will dates from the 1900s range be used? If so, that is a level of complexity that will need to be accounted for when processing YY to YYYY. Currently, all the years being processed are in the 2000s range. Example 00 >> 2000 19 >> 2019 10 >> 2010 23 >> 2023 09 >> 2009 so will an example like this be used when testing 36 >> 1936 25 >> 1925 19 >> 2019 10 >> 2010 24 >> 1924 25 >> 1925 If so, could you please provide us with a date range to work with? We don't want to have to guess which ranges will need to be processed. Kind regards