according to jython.org, which is linked in the openHAB documentation, 2.7.0 is the latest version of Jython.
Today I found the blogpost in which the release of version 2.7.1 is announced: http://fwierzbicki.blogspot.de/2017/07/jython-271-final-released.html
According the the commit messages in the repository this version contains quite a few bugfixes. But I am not sure, if this is an official version and the author of the blog really is, who he claims to be. It seems strange, that the official website has not been updated with this version.
Maybe someone here has more insight into this?