This May 2018 open access Journal of Cheminformatics article by Guenter Grethe et al., describes the first official version (RInChI-V1.00) that was released in March of 2017 and is available for download at the InChI Trust (https://www.inchi-trust.org/downloads/).
RInChI provides a standard for the representation of chemical reactions . As different databases use different methods for representing chemical reactions the adoption of RInChI and the ability to transform other representations into RInChI should allow for more thorough discovery across different databases of information related to chemical reactions. This article discusses the layers of the RInChI, the InChIKey and the Web-InChIKey. It also describes generation of RInChI from RD and RXN files, and the generation of RXN from RInChI. A database of over a million RInChI at the University of Cambridge is also described, www-rinchi.ch.cam.ac.uk .