The standard firmware currently supports DRMed (encrypted) MOBI, and it has been widely reported than MobiPocket excludes all other DRM types from EInk devices that support its DRM. So the standard Cybook does not read ePub, and in particular does not support DRMed Adobe ePubs.
The german version of the Cybook includes mobile Adobe Digital Editions and so supports Adobe ePub and PDF ebooks. It does not include MOBI support. See Cybook Gen 3 with Epub support on Thursday
and The german epub version of the Cybook
Presumably, Bookeen will continue to support two sets of fimeware going forward, one with MOBI and the other with ePub/PDF. However, this has not been confirmed so far as I know.