I had a shared iCloud Pages doc on my iPad with lots of updates which doesn't appear with those update on iPhone or Windows iCloud.com.
I tried to "restore" older versions to see if I might regrab the newest file on Windows. Failed.
And now, when I go to iPad to open the Pages doc with most recent changes, Pages says "Newer Version Needed" to open that doc. I have the newest iOS Pages.
iCloud is just too flaky for reliable/secure/predictable work!
iPad Air Wi-Fi, iOS 9, (Newest iOS )