Thanks for taking the time to file this bug and try to make Ubuntu better. The ruby2.7-dev and libruby2.7 need to be at the same version to work as expected. So you need to update your libruby2.7 to version 2.7.0-5ubuntu1.1 to make it work with ruby2.7-dev 2.7.0-5ubuntu1.1. Notice that both packages are already available in focal-updates:
$ rmadison ruby2.7-dev ruby2.7-dev | 2.7.0-5ubuntu1 | focal | amd64, arm64, armhf, i386, ppc64el, riscv64, s390x ruby2.7-dev | 2.7.0-5ubuntu1.1 | focal-updates | amd64, arm64, armhf, i386, ppc64el, riscv64, s390x $ rmadison libruby2.7 libruby2.7 | 2.7.0-5ubuntu1 | focal | amd64, arm64, armhf, i386, ppc64el, riscv64, s390x libruby2.7 | 2.7.0-5ubuntu1.1 | focal-updates | amd64, arm64, armhf, i386, ppc64el, riscv64, s390x Since this is not a bug I am marking it as Invalid. If you have any concern please comment it here. ** Changed in: ruby2.7 (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1880979 Title: A recent update to libruby2.7 breaks the installation of ruby2.7-dev. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ruby2.7/+bug/1880979/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs