Source: notmuch Version: 0.29.3-1 Severity: important Dear Maintainer, We are planning to start the ruby2.7 transition and your package failed to build against ruby2.7. Check the full build log here: https://people.debian.org/~kanashiro/ruby2.7/builds/5/notmuch/notmuch_0.29.3-1+rebuild1580865472_amd64-2020-02-05T01:17:54Z.build For now, to reproduce the failure locally you need: * experimental enabled * ruby-all-dev binary package from experimental (>= 1:2.5.7~0) For instance, you can use use the following sbuild command: $ sbuild -d unstable --build-dep-resolver=aptitude --extra-repository="deb http://deb.debian.org/debian experimental main" --starting-build-commands="apt install -y ruby-all-dev/experimental" --source-only-changes ruby2.7 should be enabled as the default ruby soon in unstable. -- Lucas Kanashiro