I'm guessing that their solution will be to put Pilots and Copilots on different update schedules and also allow for the immediate roll back of any software updates by the user. Where I don't think having one application on one OS is necessarily all that risky, what cost them in this case was the inability for the pilots to roll back to the last version that worked right after an upgrade or grab a 'backup device" from the pilot's lounge if theirs is somehow messed up. Given that the issue is not safety but more about keeping the schedule here, I imagine that the logistical costs of their solution will be a primary consideration.
No can do.
The problem isn't the iPad. Or the application. It's that one particular updated doc caused a problem.
And by flight regulations, EVERYONE has to carry the latest revision of the document. And every document is on a different update schedule.
Some documents are changed only when there are updates. Other documents have fixed expiry dates and must be updated to the latest version before that.
And at all times you must have the latest available updates - sure there's maybe a week of grace when the new edition comes out before the old edition expires, but that's about it.
In the paper world, people were actually employed to go through all 35lbs of documents ensuring the latest versions of every page were present (pages are usually supplied as differences in binders, so you remove the old page and stick in the new page. Pages were versioned (typically by date) and there's often a cover sheet saying what's the latest version of each page (updated every time there's an update).
Of course, if you have hundreds of pilots each having to do this, eventually the human version of patch(1) will screw up, so you need to double check for this.
It's why EFBs have been so widely embraced - not having to have someone check 35lbs of documents practically daily, not having to have a whole infrastructure set up to distribute updates, not having to spend time updating documents, etc, it's a terrible chore.
In fact, given the number of updates and how long it's been going on, it's surprising it's only happened once that an update screws up - I'm sure in the past with paper it happened dozens or hundreds of times a day because updates happen that often, usually to different subsets of the pilots.