Description
This will be pretty big task on its own, so help would be welcomed (it possibly could have own maintainer).
Mail client shall have all useful features of M2 plus support for useful stuff that everybody always wanted but was never added there (like PGP).
Mail client and RSS reader should be separated modules, but sharing single panel and similar UI design. Also all PIM related modules should use common storage for contacts, possibly using backends for integration with system wide contacts database (like for example KDEPIM). There used to be such modules available for Qt4 (as part of Qt Mobility) but their API was overcomplicated and as of now there is no direct replacement for them yet (but may be available in near future, so some research would be great).
There exists some pure Qt reference implementations for mail protocols (for example as plugins for QtMessaging - again, part of Qt Mobility), but if there is nice and clean library with proper Qt bindings around (and compatible license) then we could make use of it.