We've completed implementation of Epics and it will be released soon. We changed our development process recently and now every feature is split into two: MVF - minimal viable feature and MMF - minimal marketable feature. These two features has a gap about 1 month, so we accumulate feedback about MVF and use this information to enhance the feature dramatically.
Let me describe what you can already do with Epics in the upcoming release.
Epic is an entity above Feature. Quite often you want to have one more level of hierarchy for requirements, and Epic can be handy:
For example, you can create a board that shows Features by Epics.
More interesting view is a full drill-down from Epics to User Stories. Here is a setup for that case:
As a result, you can see full backlog hierarchy:
Epic details view is quite familiar. It has usual properties and contains a list of related Features as well as Epic progress tracking information. So now you can track progress on a higher level:
Epic is quite similar to Feature entity and you can define terminology for Epic, create custom fields, set permissions and customize its workflow:
You can export and import Epics, print Epics, access them via REST API, create Timelines with Epics, etc.
We are looking into feedback! If you need Epics, please, use them and let us know what you miss.