Package: thuban Severity: grave Version: 1.2.2-2+b1 thuban: Installed: (none) Candidate: 1.2.2-2+b1 Version table: 1.2.2-2+b1 0 500 http://ftp.tw.debian.org/debian/ unstable/main i386 Packages The following packages have unmet dependencies: thuban: Depends: libgdal1-1.6.0 which is a virtual package.