PAR files not supported

Hi

I m upgrading portal 7.0 to 7.31 .

I get an error during during shadow import phase thar .PAR files are no longer supported and should be converted to WDA files.

Is the PAR to WDA conversion done by Portal or Basis.

Also .PAR migration tool comes with NW 7.3 and we are on NW 7.0 , how do we get this tool to do the conversion on NW 7.0 or the portal developers should be able to do it.

Thanks and Regards

Tushar