Development of the next release of siunitx has gone quite smoothly: I’ve added a few new features, and there is now nothing outstanding for v2.4. So it is time to ask for some volunteers to test the code.
In terms of new features, I have added the a choice of rounding modes modes the ability to compress down exponents in ranges and lists, both long-standing feature requests. In response to a recent TeX.sx question, siunitx can now also turn exponents into unit prefixes. At a lower level, I’ve also altered some of the options internally so fewer of the assume math mode.
To test, please download the ready to install TDS-style .zip file and install it locally. You should then be good to go. Feedback as a bug report or by e-mail welcome, as always. Assuming there are no problems, I’d expect to upload to CTAN by the end of the month.