iPad Error : Could not parse saved plist - Error decompressing data

I have been running OmniGraffle 2.9 on my iPad for some time and recently purchased Omnigraffle 7 for MacOS so I can view and edit files on both devices.

I have configured an account on OmniPesence server and can see my saved files in both devices.

Whenever I try to open on OmniGraffle file created on the Mac on my iPad, I receive the following error

“Could not parse saved plist. Error decompressing data”

I have tried saving to dropbox and iCloud and also e-mailed the file from my Mac to iPad, but all files created on my Mac return the same error when opening on my iPad.

I am able to create files iPad, save them to the OmniPresence server and then open on my Mac,
but as soon as I edit and resave on my Mac, I am no longer able to open these files on my iPad.

Please help