The ImportData related files in the \Shared and \App_Code\Shared folders are replaced by new versions from the ProjectTemplates folder.
During migration, these ImportData files are replaced with new versions:
…\Shared\ImportData.ascx
…\Shared\ImportData .ascx.cs (vb)
…\Shared\SelectFileToImport.ascx
…\Shared\SelectFileToImport.ascx.cs (vb)
…\App_Code\Shared\ImportDataItems.cs (vb)
…\App_Code\Shared\CsvParser.cs (vb)
…\App_Code\Shared\Parser.cs (vb)
Customizations you have made to these files will not be retained. If you have customized these files, then you must re-apply your customizations to the new files.
After migration, re-apply any customizations you may have made to the original ImportData files to the new ImportData files in your application.
Version 6.0 Application Migration