We are pleased to announce the release of BioRuby 1.5.1. In this new release, NCBI Entrez web client classes, Bio::NCBI::REST and Bio::PubMed, are changed to use HTTPS instead of HTTP, to prepare NCBI website transitioning to HTTPS. For more information, see RELEASE_NOTES.rdoc and ChangeLog. The archive is available for download from the following links.