Dear Maintainer, your package depends on libeigen3-dev. The upstream released a new major version of this mathematical library, 5.0.0. Some basic information about new features and changes in this version can be found here: https://libeigen.gitlab.io/releases/5.0/ This is a major version change and may require code changes in packages depending on eigen3. The key breaking changes include: - Minimum required C++ standard is now C++14 - Changes in the build system integration - Some API name changes g2o FTBFS with libeigen3-dev 5.0.1. The full build log is available at: https://debusine.debian.net/debian/developers-gladk-eigen3/artifact/3755814/ Here is the most probably relevant part of the failing build log: =========================================== The following information may help to resolve the situation: The following packages have unmet dependencies: sbuild-build-depends-main-dummy : Depends: debhelper (>= 11) but it is not going to be installed Depends: cmake but it is not going to be installed Depends: libopenblas-dev but it is not going to be installed Depends: libsuitesparse-dev but it is not going to be installed Depends: libopengl-dev but it is not going to be installed Depends: libqglviewer-headers but it is not going to be installed Depends: libeigen3-dev but it is not going to be installed Depends: libglut-dev but it is not going to be installed Depends: libtbb-dev but it is not going to be installed Depends: libmetis-dev but it is not going to be installed Depends: libceres-dev but it is not going to be installed Depends: libgmock-dev but it is not going to be installed E: Unable to satisfy dependencies. Reached two conflicting assignments: 1. libceres-dev:amd64 is selected for install because: 1. sbuild-build-depends-main-dummy:amd64=0.invalid.0 is selected for install 2. sbuild-build-depends-main-dummy:amd64 Depends libceres-dev 2. libceres-dev:amd64 Depends libeigen3-dev (< 3.4.1) but none of the choices are installable: - libeigen3-dev:amd64=3.4.0-5 is not selected for install apt-get failed. E: Package installation failed =========================================== libeigen3-dev_5.0.1-1 is available in experimental. When this package version lands into unstable (probably at the beginning of June 2026), this bug will be increased in severity to serious. Thanks, Anton