How does Versions work with iCloud? Just wondering how, if at all, Versions on Pages for Mountain Lion (10.8) works with iCloud, specifically in relation to iOS 5 devices.

My own testing seems to indicate that a Pages document created on the Mac saves versions in iCloud that you can revert to but only on the Mac (can't find an iOS interface for Versions). However, if I create a document on Pages for iOS (forcing an upload to iCloud after each edit) I can't revert to previous versions made on iOS, even on the Mac. One time, when I tried to do this, I saw a message saying the file is stored on a volume which doesn't support permanent version storage. However I have been unable to reproduce this message.

Can anyone enlighten me as to how Versions is supposed to work with iCloud? Is it a Mac-only feature, not available on iOS? If so, how best to guard against unwanted edits on iOS? Should I just prevent the doc from being uploaded to the cloud until I am happy with it, and use the undo / redo feature?

As I understand it, we only have Versions on the Mac because we also have Autosave. On iOS all saving (to the cloud) is done manually (the equivalent of the old command-s on Snow Leopard) thus eliminating the need for iOS versions. Have I got the correct picture here?

Sorry for the long post! I'd really appreciate any replies.
iCloud itself does support document revisions, and my understanding is that it does the same job OS X does for versions stored locally (keeps track of all the small changes, and is in charge of assembling all the chunks into different versions). So any OS X app that supports versioning and iCloud storage should handle both together seamlessly, the same as if it's stored locally. It sounds like you're seeing the expected results in this case.

On iOS it's a bit more complicated - apps have access to other revisions of the document, but because there's no standard way for a user to see different versions (as in OS X), it's up to the app developer to deal with this. I believe the recommended practice for iOS apps is to only keep versions as necessary (for example, dealing with two conflicting versions).

Based on my understanding, if you create a document on iOS, then edit it on OS X, you should be able to view the revisions on OS X, but iOS will only show the "current" one, and OS X will probably only include one iOS-edited version of the file, with whatever versions were edited on OS X. However, this all depends a lot on how the iOS developer implements iCloud storage, and based on my reading of the developer documentation, if an iOS app has what it can satisfactorily decide is the canonical up-to-date version of a document, it may discard all previous versions. That may be why you were running into issues with iOS-created Pages documents.

Ultimately, iCloud is a pretty complex thing, and while they go to great lengths to make it seem simple for the user, some of that complexity can get in the way.

TL;DR version: using OS X only, versions should sync fine. Bringing iOS into the mix can change things depending on the developer's implementation.