Package: heimdal-clients Version: 7.1.0+dfsg-9 kftp and kftpd are no longer part of Heimdal since version 7.0.1. It is therefore incorrect for heimdal-clients to claim that it Provides: ftp and for heimdal-servers to claim that it Provides: ftp-server
I suspect that the corresponding Conflicts: can also be dropped but haven't actually tested this. If true, then bug 236902 may be considered to be fixed.