I tried out the exchange between Cubase Projects and Cubasis Projects:
Cubasis to Cubase:
In principle it works, but for Midi-Drumsets from Cubasis there is no valid assignment to a drumset in Groove Agent 5 SE (=> as in the past, no transfer from a Microsonic Drumset to a Halion Sonic Drumset). This worked with the old transfer method using the Cubasis importer for Cubase (up to Cubase 13).
Cubase to Cubasis:
It seems to work with Cubase audio tracks to Cubasis audio tracks, and with Cubase instrument (!) tracks to Cubasis Midi Tracks, but not with Cubase Midi Tracks to Cubasis Midi Tracks. There seems to be a mismatch, don’t know whether on Cubasis or Cubase side.