How to get a list of Tasks whose FixVersion is different to that of its Epic

[Lee Cash]

Hi, 

We like to keep the FixVersions of our Tasks and their parent Epics in sync. Sometimes they do go out of whack because a task overspills and gets its FV updated to the new release but it remains inside an Epic associated with a closed release. 

I'm looking for JQL that essentially returns: 

Tasks whose FVs don't match that of their parent Epic

I don't mind manually cycle through the Fix Versions if I have to (we only have a few).

I've been playing around with parentOf, issuesInEpics etc but I can't seem to get it right. 

Any help is greatly appreciated. 

Thanks, 

Lee