Comment 4 for bug 1442734

With me, this bug appeared right after upgrading to Ubuntu 15.04. Since the plug-in installer (the part that tries to make the gpg check) has been buggy for quite a while,so I suspected yet another bug in that area. However, the release notes (http://hplipopensource.com/hplip-web/release_notes.html) says that the version 3.15.2, which comes with Vivid, does not support Vivid yet. We need 3.15.4 to get support for Vivid. I have not tried installing that version yet because I would rather like to get it with Ubuntu's software updates, so I do not know if it would fix the bug or not.