Message Archiving is an Enterprise Only feature, which is why there's no reference point for the Pro version in that chart. With Archiving, daily messages are stored in .EML format and can be found in the Archive folder. Then subsequent days are zipped up...but retain the .EML format. There aren't any GRP files in the archive. We also have a utility for extracting .EML files from a GRP. If you'd like it, just email sales@ and they can send it to you.