Thanks to Opa (possibly due to that fact that we know how to use it at its best), we are able to develop features very quickly. I would say that what we need most is to optimize the UX and little details that matter to refine them over time. But overall, I think we can go technically much farther that Zimbra/Roundcube. But to achieve more popularity, we will need to beef up some marketing aspects!
We maintain a roadmap: https://github.com/MLstate/PEPS/wiki/Roadmap
Thanks to Opa (possibly due to that fact that we know how to use it at its best), we are able to develop features very quickly. I would say that what we need most is to optimize the UX and little details that matter to refine them over time. But overall, I think we can go technically much farther that Zimbra/Roundcube. But to achieve more popularity, we will need to beef up some marketing aspects!