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

rdkit FTBFS with libeigen3-dev 5.0.1. The full build log is available at:

https://debusine.debian.net/debian/developers-gladk-eigen3/artifact/3761129/

Here is the most probably relevant part of the failing build log:
    ===========================================

Dear maintainers,

eigen3 5.0 (libeigen3-dev 5.0) is now in unstable, so these FTBFS bugs are
release-critical.  I am therefore raising their severity to serious.

Regards,

Anton

We believe that the bug you reported is fixed in the latest version of
rdkit, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 1136322@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Andrius Merkys <merkys@debian.org> (supplier of updated rdkit package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Tue, 08 Sep 2026 05:59:04 -0400
Source: rdkit
Architecture: source
Version: 202603.4-2
Distribution: unstable
Urgency: medium
Maintainer: Debichem Team <debichem-devel@lists.alioth.debian.org>
Changed-By: Andrius Merkys <merkys@debian.org>
Closes: 1136322 1146843
Changes:
 rdkit (202603.4-2) unstable; urgency=medium
 .
   * Backport modified upstream commit to fix FTBFS with eigen3 >= 5.0.0
     (Closes: #1136322)
   * Backport upstream commit increasing test tolerance to fix test failure on
     arm64 (Closes: #1146843)
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