Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint File Formats
Install this compatibility pack if you would like to open, edit, and save documents, workbooks, and presentations that were created in the newer versions of Word, Excel, and PowerPoint. NOTE: The Office Compatibility Pack is being retired in April, 2018. At that time, it will no longer be available for download and will no longer receive security updates.
But I have a copy of FileFormatConverters.exe saved.