CONVERTING A MICROSOFT TEMPLATE TO BE USED WITH LIBRE OFFICE

What you are missing is that there are file layout differences between the various editions of the same version of MSO.

All those differences are hierarchic.

That does not negate the differences in the file format of the various editions of the same version.

You can read all the files of earlier version and have a way to ignore unsupported elements from the higher versions.

Only if file incompatibility is acceptable to the user. Something that is apparently more true of MO users than ODF users.

+1

Pete