Adobe PageMaker used several file types for its documents in different versions, so it should be quite possible to open the older formats like PMD and save them in the later PM5 format. However, Adobe PageMaker is no longer sold, so finding it could be tricky.
Convert Adobe PageMaker document to Adobe PageMaker 5 document file.
We found 2 software records in the database related to .pmd to .pm5 file format conversion.
Microsoft Windows software - convert pmd to pm5 on Windows
One of the first desktop publishing programs on market
Convert from pmd file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned pmd to pm5. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
Apple macOS / Mac OS X software - convert pmd to pm5 on OS X
Mac version of once popular publishing program