XSitePro 2.5 is compatible with XSE files created with earlier versions of XSitePro.
If you have any XSE files you created with an older version of XSitePro, or someone sends you an XSE file that they created using XSitePro, you should have no problems importing it.
To import an XSE file from a previous version of XSitePro follow the normal procedure for importing XSE files detailed above and XSitePro will convert everything over to the new format automatically.
Note: although it is possible to import XSE files created in previous versions of XSitePro into XSitePro 2.5, it is not possible import XSE files created in XSitePro 2.5 into older versions of the software (i.e. 1.x). This is because there is functionality in XSitePro 2.5 that was not in older versions and this would obviously cause problems.