Google Drive is Google's file sync app that lets you store all of your files online alongside your Google Docs documents, and keep them synced with all of your devices.
Tie rejected proof comments to the next design revision.
Your designer gets the changes reviewers requested, tied to the rejected file version, with a link back to the approval.
Flag outdated print proofs and ask for the current file.
Your reviewers can decide on the intended creative file. The Agent flags outdated versions and asks the owner for the current one.