Excel 2007. Prior it was impossible due to file format limits. Row limit was 64k, i think. Not sure what the Col limit was. Not sure what or if there limits are

Excel 2007. Prior it was impossible due to file format limits. Row limit was 64k, i think. Not sure what the Col limit was. Not sure what or if there limits are since the move to the xlsx format. Despite doing Excel addin development in finance, i never hit a limit in post 2007 excel.