Originally Posted by gmayor

My Document Converter add-in will update the files to the latest format and retain the file creation and last modified dates (not the last accessed date) . It will also retain the original files, which is probably sensible - at least while testing.

Test it with a small number of documents, copied to a new folder, to ensure that it does what you require, before letting it loose on a larger selection of documents.

It does not work with Office 2007!