I have 2003 power point. A company sent me a ppt to use probably on that same or similar dated system as it is compatible and usable in my 2003 ppt in my computer.

My partner has a new computer using a more advanced PPT. He made some changes, and now my ppt will not accept his changes. Mine is .ppt. His is .PPT. What can I do to use his power point changes, other than updating my whole power point system? It appears I can go up with changes, but he cannot come down with changes.