released a new edition about every seven to ten years. The 15th edition (2003) was revised to reflect the emergence of computer technology and the internet in publishing, offering guidance for citing electronic works. Other changes include a chapter on American English grammar and use, and a revised treatment of mathematical copy. In August 2010, the 16th edition was published simultaneously in the hardcover and online editions for the first time in the Manuals history. In a departure from the earlier red-orange cover, the 16th edition features a robin's-egg blue dust jacket (a nod to older editions with blue jackets, such as the 11th and 12th). The 16th edition featured "music, foreign languages, and computer topics (such as Unicode characters and URLs)". It also expands recommendations for producing electronic publications, including web-based content and e-books. An updated appendix on production and digital technology demystified the process of electronic workflow and offered a primer on the use of XML markup. It also includes a revised glossary, including a host of terms associated with electronic and print publishing. The Chicago system of documentation is streamlined to achieve greater consistency between the author-date and notes-bibliography systems of citation, making both systems easier to use. In addition, updated and expanded examples address the many questions that arise when documenting online and digital sources, from the use of DOIs to citing social networking sites. Figures and tables are updated throughout the book, including a return to the Manuals popular hyphenation table and new, selective listings of Unicode numbers for special characters. In 2013, an adapted Spanish version was published by the University of Deusto in Bilbao, Spain. In April 2016, the publisher released The Chicago Guide to Grammar, Usage, and Punctuation, Bryan A. Garner's expansion of his Chicago Manual of Style chapter on the topic, and coinciding with the release of the new edition of Garner's Modern American Usage. The 17th edition was published in September 2017. It offers new and expanded style guidelines in response to advancing technology and social change. It also includes new and revised content reflecting the latest publishing practices and electronic workflows and self-publishing. Citation recommendations, the glossary of problematic words and phrases, and the bibliography have all been updated and expanded. In the 17th edition, email lost its hyphen, internet became lowercase, the singular "they" and "their" are now acceptable in certain circumstances, a major new section on syntax